Strategy & Math Flashcards

(166 cards)

1
Q

cos 0 30 45 60 90

A
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2
Q

sin 0 30 45 60 90

A

1

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3
Q
  • SI units:
    • Femto
    • Kilo
    • Deci
A

Femto

  • 10-15

Kilo

  • 103

Deci

  • 10-1
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4
Q

SI Units:

  • Mega
  • Pico
  • Hecto
A

106

10-12

102

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5
Q

SI Units:

  • Tera
  • Nano
  • Centi
A

1012

10-9

10-2

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6
Q

SI Units:

  • Deca
  • Giga
  • Micro
  • Milli
A

101

109

10-6

10-3

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7
Q

Convert 650 nm to SI units

A

650 x 109

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8
Q

Const. force (not velocity!) causes WHAT acceleration?

A

constant acceleration

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9
Q

When you throw a baseball, when is the only time it is accelerating?

A

Only when it is in contact with your hand

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10
Q

Increasing something by 25% is the same as multiplying it by what?

A

x 5/4

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11
Q

Define “mass”

A

the measure of an object’s inertia

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12
Q

Define “inertia”

A
  • the ability of an object to RESIST its change in velocity
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13
Q

Where on a mass/object is its “Center of Gravity?”

A

is at the center of the mass/object

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14
Q

Where is the “Center of buoyancy?”

A
  • at center of mass of the FLUID displaced by the submerged object
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15
Q

Scalar or Vector?

Mass

A

scalar

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16
Q

Scalar or Vector?

temperature

A

scalar

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17
Q

Scalar or Vector?

velocity

A

vector

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18
Q

Scalar or Vector?

speed

A

scalar

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19
Q

Scalar or Vector?

displacement

A

vector

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20
Q

Scalar or Vector?

acceleration

A

vector

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21
Q

Scalar or Vector?

force

A

vector

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22
Q

Scalar or Vector?

work

A

scalar

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23
Q

Scalar or Vector?

energy

A

scalar

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24
Q

Scalar or Vector?

weight

A

vector

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25
Scalar or Vector? charge
scalar
26
Scalar or Vector? electric field
vector
27
Scalar or Vector? magnetic field, ***B***
vector
28
Scalar or Vector? time
scalar
29
Scalar or Vector? momentum
vector
30
Scalar or Vector? impulse
vector
31
Scalar or Vector? density
scalar
32
Scalar or Vector? torque
vector
33
What are the 4 questions that test **conceptual** understanding?
1. Can I **visualize** it? 2. Can I **draw** a picture/graph/diagram of it? 3. Can i explain it to someone in **layman's** terms? 4. Can i think of and describe real-life **examples**?
34
* Area of triangle * formula=?
**A****tri****=1/2 bh**
35
Vol of sphere formula
**Vsphere=4/3 πr3**
36
SA of sphere formula
4pir^2
37
Manipulating equations mnemonics
SSISDDODIOSD
38
sqrt 2=
1.4
39
sqrt 3=
1.7
40
sqrt 2/2=
.7
41
sqrt 3/2=
.9
42
product of [H][OH] always equals:
1x10^-14
43
Doppler effect formula
deltaf/fs=v/c
44
Be careful of S.N.E.W.L
Qualifiers (Write these down!) "StrengthensNot ExceptWeakensLeast"
45
tan0=
sin0/cos0
46
sin^2x+cos^2x=
1
47
11^2
121
48
12^2
144
49
13^2
169
50
14^2
196
51
15^2
225
52
Multiplying 2 vectors: If answer is scalar, (ie work), also mult by what?
cos0
53
multiplying 2 vectors: if answer is a 3rd vector (ie torque), also multiply by what?
sin0T=Frsin0
54
Decimal equivalent:1/5
.2
55
Decimal equivalent:1/8
.125
56
Decimal equivalent:1/9
.11
57
For fractions where numerator is higher (like 13/5), what should you do to solve?
Create compound fraction: 5x2=10, left w/ 3/5 13/5 becomes 2x (3/5)
58
For fractions where denominator is larger, what should you do to solve?
"High/Low" methodChange denominator to 1 digit higher or 1 digit lowerex:3/7 changed to 3/6 and 3/8. Must be a little less than .5
59
When multiplying with scientific notation, what happens to the exponents?
You add them together
60
When dividing with scientific notation, what do you do with the exponents?
You subtract them
61
* Estimating Fractions **29/4** =?
**=7.25** ## Footnote 4 x **7**=28 **¼** is left behind
62
* Estimating Square Roots * "High/Low" Method What is the **square root** of 72?
* **√81**=9 * √**64**=8 ∴ the square root of 72 is somewhere **in between**, so about **8.5**
63
* **Surface Area** of a Sphere * Formula=?
**SA****sphere****= 4πr2**
64
* Trigonometry * **All** of the angles in any triangle must add up to?
180°
65
Trigonomic Relationships * sinθ= * cosθ= * tanθ=
sinθ=**O**pp/**H**yp cosθ=**A**dj/**H**yp tanθ=**O**pp/**A**dj ​"SOHCAHTOA"
66
Converting from **DEGREES** to **RADIANS** * π radians=? * 2π radians=? * How many **radians** are in **ONE CIRCLE?** * ∴, if something is turning at **12** rad/sec, it is making approximately ___ revolutions/sec
* π radians=180° * 2π radians=360° There are approximately **6** radians in **ONE CIRCLE** * **∴,** if something is rotating at 12 rad/sec, it is making **2 revolutions/ sec**
67
Trigonomic Relations * What are the **INVERSES** of sin, cos, and tan?
* sin-1 * ****_co_**secant** * cos-1 * **secant** * tan-1 * co**tangent**
68
Trigonomic Relationships * tanθ= ?
tanθ=sinθ / cosθ
69
Linear & Non-Linear Graphs * What does a graph look like for: **y=x**
70
Linear & Non-Linear Graphs * What does a graph look like for: **y = 1/x**
71
Linear & Non-Linear Graphs * What does a graph look like for: **y=x2**
72
Linear & Non-Linear Graphs * What does a graph look like for: **y = |x|** *(Absolute Value)*
73
Linear & Non-Linear Graphs * What does a graph look like for: **y = x3** (Cubic)
74
Linear & Non-Linear Graphs * What does a graph look like for: **y = √x**
75
Linear & Non-Linear Graphs * What does a graph look like for: **y= 3√x** *(Cube Root)*
76
Linear & Non-Linear Graphs * What does a graph look like for: **y = ln x** *(Logarithmic)* How does it look different than **y= logx?**
77
Linear & Non-Linear Graphs * What does a graph look like for: **y = *sin*x**
78
Linear & Non-Linear Graphs * What does a graph look like for: **y = *cos*x**
79
Linear & Non-Linear Graphs * What does a graph look like for: **y = ax ** (Exponential)
80
Linear & Non-Linear Graphs * What does a graph look like for: **y = 1/x** *(Reciprocal)*
81
Linear & Non-Linear Graphs * For the equation **X= ½at2** * Which of the following relationships will be **LINEAR?** * Which will be **NON-LINEAR?** 1. **​X vs. t** (or t vs. X) 2. **X vs. a** (or a vs. X) 3. **a vs. t** (or t vs. a)
**X=½at2** ## Footnote 1. ​NON-linear 2. Linear 3. NON-linear
82
Linear & Non-Linear Graphs What does a graph look like for: **y = *tan* x**
83
Graphs used as _Answer Choices_ * If a variable is changing **exponentially**, will be **linear** or **non**-linear on: * a **semi**-log graph? * a **log-log** graph?
The log of an exponential function becomes linear, so exponential functions graphed on **semi**-log axes end up being **linear** * **​...**AND a **linear** function would be **non**-linear If the exponential function is graphed on **log**-**log** axes, the function will be **non-linear** * The table below may be helpful* * The semilog graph described is for a **linear X-axis** and a **logarithmic Y-axis** (log-lin type not lin-log)
84
Graphs used as _Answer Choices_ * Describe: * a **semi**-log graph
* A semi-log graph has a **logarithmic** scale on one axis, but a **linear** scale on the other axis
85
Graphs used as Answer Choices * Describe: * a **log-log** graph
A log-log graph has a **logarithmic** scale on **BOTH** axes
86
Manipulating Equations **ay=vx2/cq** * How are **a** and **y** related to each other?
inversely
87
Manipulating Equations **ay=vx2/cq** How are **x** and **q** related to each other?
directly
88
Manipulating Equations **ay=vx2/cq** How are **a** and **q** related to each other?
directly
89
Manipulating Equations **ay=vx2/cq** How are **a** and **c** related to each other?
inversely
90
Manipulating Equations **X=½at2** What will happen to **time** if the distance (x) is **tripled?**
**x∝t2** * If the distance traveled (x) increases by a factor of **three** (3), then time must increase by some factor that, when **squared**, will **also** equal a factor of three * This number is the **square root of three**, so time will increase by a factor of **1.7**—* * or be **1.7 TIMES larger** than it was originally*
91
**√3=**
**1.7**
92
Well-designed research must have a **hypothesis** that is....?
a **Testable** hypothesis * basically, it can be used to verify a clear **YES** or **NO** answer
93
Types of Research * Decribe Experimental or "**Basic Science**" Research * What kind of environment is it conducted in? * Is it conducted on Human subjects? * What does this type of research allow investigators to have? * The main goal of this type of research is to indicate...?
_**Experimental** or “Basic Science” Research_ * **Laboratory** research conducted in a **highly controlled environment;** * **NOT** on human subjects! * This type of research allows investigators to have the strictest level of **control** over all possible variables and conditions * Experimental research is therefore thought to be the most **reliable** way to indicate **CAUSATION**
94
Types of Research * Human Subjects Research * Where is it conducted? * What is a common example of this type of research? * How does it compare (in **efficiency** and level of **control**) to "Basic Science" research? * Are its conclusions **more** or **less** definitive? What are the **2 Types** of Human Subjects Research?
**_Human Subjects Research_** ***2 Types: Experimental & Observational*** * Research conducted **outside** the laboratory, often on **human** subjects * _Drug trials_ are a common and familiar example * Has less control over conditions than in "**Basic Science"** research* * making conclusions **less** definitive* * For example, a study drug may **fail** to show decreased blood pressure in some subjects * However, it is **later** discovered that all participants did **not** follow the strict low-sodium diet required by the study guidelines * This was thought to influence blood pressure measurements in those patients
95
Human Subjects Research * Describe "**Experimental**" Research * Research involves a specific ________ controlled by the \_\_\_\_\_\_\_\_. * Subjects are separated into _____ and ________ groups
* Research involves a specific **intervention** controlled by the **investigator** * Subjects are separated into **control** and **treatment** groups. * e.g., To test the efficacy of a new drug, patients with allergies are separated into groups randomly and given either the **drug** (treatment) or **placebo** (control)
96
Human Subjects Research * Describe "**Observational**" Research * Investigator _______ data ***WITHOUT....***? (2)
* Investigator observes data **WITHOUT:** * **​**Direct control over the variables, **OR** * Implementation of interventions _Example_: An investigator reviews case studies from COPD [chronic obstructive pulmonary disease] patients and examines demographic information and lifestyle choices in an attempt to identify risk factors associated with COPD)
97
Medical Ethics * Describe (in general) "**Beneficence**" * One important aspect of this is *ending* a study because of...?
***DO GOOD.*** ## Footnote * Doctors and researchers have an obligation to promote the welfare of patients or study participants * Patient welfare should always be a primary consideration in study design and execution _ENDING A STUDY BECAUSE OF **POSITIVE** ("GOOD") RESULTS_: * One classical application of beneficence in human subjects research is the obligation to END an experimental study when it is clear a drug or intervention results in obvious benefit * This may sound **counterintuitive**, but remember that each study **must** have control groups * If a drug is found to save the lives of dying cancer patients..... * it is **NOT** ethical to continue the study long-term and thereby save the lives of those in the treatment groups * *...while those in the control groups are **withheld** from taking a drug researchers _know_ could help them*
98
Medical Ethics * Describe (in general) "**Nonmaleficence**" * One important aspect of this is *ending* ​a study because of...?
**DO NO HARM** ## Footnote * This is the physician’s oath, but applies equally to **researchers** * Doctors and researchers have an obligation to not harm their patients or study participants _ENDING A STUDY BECAUSE OF **NEGATIVE** ("BAD") RESULTS:_ * Researchers are similarly obligated to end a research study *as soon as* it is verified that a treatment **harms** the subjects * Most early research that is criticized today is drawn into question because it violated this principle * The famous psychology study involving “Little Albert,” for example, while revealing evidence about conditioning, is now thought to have had an **unethical** impact on the young child involved :( * Albert was conditioned to have severe generalized phobias of animals and the study involved obvious emotional trauma to Albert.
99
Medical Ethics * Describe (in general) "**Autonomy**"
**_Patient autonomy and informed consent_** * Physicians and researchers have an obligation to: * **Inform** patients or study participants, and * Allow them to **make decisions** about their own health and treatment At times, *some* deception (e.g., placebo) is **necessary** to effect research * However, this should be the **minimal** amount possible, the truth should be revealed as **soon** as possible, and deception in general should be approved by an Internal Review Board (IRB)
100
Medical Ethics Describe (in general) "**Justice**" * Hint: "Equal..."
Equal **treatment** of all people * Equal allocation of **resources**, to the extent possible * ..without bias, prejudice or discrimination.
101
Observational Research Study Types * Describe a "**Cohort Study**" * Cohort Studies usually employ \_\_\_\_\_\_\_s to demonstrate a \_\_\_\_\_\_ * Give an example Hint: A "cohort" is an ancient Roman military unit, comprising six centuries, equal to one tenth of a legion ***THINK: Cohort = GROUP***
**_Cohort Study_** * is a **longitudinal** study observing characteristics (usually risk factors) of members of a cohort across time Cohort studies usually employ **correlations** to demonstrate a **relationship** _EXAMPLES:_ * Smokers (Cohort A) were three times **more** likely to develop lung cancer before the age of 50 than non-smokers (Cohort B) * A statistically significant correlation (r = 0.84, p \< 0.01) exists between socioeconomic status and frequency of pre-term births Notice that this is **NOT** the manipulation of an independent variable, **THEN** observing outcomes * Scientists are simply observing data about people or populations **as it exists** and **looking for relationships**
102
Observational Research Study Types * Describe a "**Cross-Sectional** Study" * Give some examples
**_Cross-Sectional study_** * is the analysis of data collected from a population or sample **AT ONE SPECIFIC TIME** * ...compared to ***across a time period*** for cohort studies _EXAMPLES:_ * A survey of the U.S. population to determine the current prevalence of a disease * A study examines blood pressure among those with incomes above $100K/year and those below $100K.
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Observational Research Study Types * Describe a "**Case-Control** Study" * By design, a Case-Control Study is always \_\_\_\_\_\_\_\_ * Give an example
**_Case-Control Study_** *By design, a Case-Control Study is always **RETROSPECTIVE*** * Is an observational study of individuals in the population **WITH** a condition present * ...and comparison of that group to a control group of persons **WITHOUT** the disease **IN THAT SAME POPULATION** (i.e., "reference group") *Most famous Case-Control Study is the one is the study that linked **lung cancer** to **smoking*** _EXAMPLE_: * There is a suspicion that zinc oxide (the white non-absorbent sunscreen traditionally worn by lifeguards) is **more** **effective** at preventing sunburns that lead to skin cancer than absorbent **sunscreen lotions** * A case-control study was conducted to investigate if exposure to zinc oxide is a more effective skin cancer prevention measure * The study involved comparing a group of former lifeguards that **HAD** developed cancer on their cheeks and noses (cases) to a group of lifeguards (same population) **WITHOUT** this type of cancer (controls) * ...and assess their prior exposure to: * zinc oxide **OR** * absorbent sunscreen lotions * This study would be **retrospective** in that the former lifeguards would be **asked to recall** ("Recall Bias") _which type_ of sunscreen they used on their face and approximately _how often_
104
Observational Research Study Types * What are some Pros & Cons of: * **Cross-Sectional** Studies
105
Observational Research Study Types * What are some Pros & Cons of: * **COHORT** Studies
106
Observational Research Study Types * What are some Pros & Cons of: * **Case-Control** Studies Also: *What kind of outcome are these studies useful for?*
*Useful for RARE outcomes*
107
Observational Research Study Types * Differentiate b/t: **Prospective** & **Retrospective** Cohort Studies * What's going on wrt the **Exposure** & **Outcome**?
108
Independent vs. Dependent variables * Differentiate b/t the two * For each: * "Also called the ____ variable" * "It can be thought of as the....?" * What axis of a graph does each go on? HINT: "**DRYMIX**" or "**I'M** a **DR.**"
**_INDEPENDENT VARIABLE_** * The variable that gets: * **MANIPULATED** (or rather...) changed **_BY THE INVESTIGATOR!!_** * Also called the “**predictor** variable.” It can be thought of as the “**CAUSE**” * Always goes on the **X**-axis **_DEPENDENT VARIABLE_** * The variable ***MEASURED*** * ....as a *response to changes* in the **IN**dependent variable * Also called the “**outcome variable**” It can be thought of as the “**EFFECT**” * You can't "Add" a ***De**pendent* Variable * i.e., you can "add" an outcome...you can only "add" something that **will** **change** the outcome * Always goes on the **Y**-axis
109
Independent vs. Dependent variables * Identify the **independent** and **dependent** variables in the following scenarios: 1. Time spent studying and test score 2. Gas mileage and octane rating of the gas used 3. Dosage of medication used and lab rat survival rate 4. Level of aggression and amount of exposure to violent video games
1. Independent: Time Spent studying * Dependent: Test score 2. Independent: Octane rating of gas * Dependent: Gas mileage 3. Independent: Dosage of medication * Dependent: Survival Rate 4. Independent: Exposure to violent VG's * Dependent: Lvl of aggression
110
Study Methods * Define a "**Control Group**"
**_Control Group_** A group or trial in which ***ALL*** conditions and environmental factors are ***IDENTICAL*** to the treatment group-- ***EXCEPT*** for the treatment itself!!
111
Control Groups * Define a "**POSITIVE** Control" * What purpose do they serve in an experimental study? * An experiment results in the ability of bacteria to grow on a petri plate containing antibiotic (**POSITIVE** control=?)
**_POSITIVE control_** * Is a group given a treatment with a **KNOWN** **OUTCOME** PURPOSE: * The positive control can be **compared** to the **unknown** outcome of whatever treatment is being studied _EXAMPLE_: * If your experiment results in the ability of bacteria to grow on a petri plate containing antibiotic, your **positive** control will be bacteria that are **known** to carry the appropriate drug resistance marker Even if **none** of your experimental bacteria grow, as long as there is growth of the positive control * ....you know that growth was at least **POSSIBLE**
112
Control Groups * Define a "**NEGATIVE** Control" * What purpose do they serve in an experimental study? * HINT: What can they help ***expose?*** * An experiment results in the ability of bacteria to grow on a petri plate containing antibiotic (**NEGATIVE** control=?)
**_NEGATIVE control_** * is a group that does **NOT** receive any condition or treatment * ...and for which **NO** outcome is expected PURPOSE: * To help expose **CONFOUNDING** variables _EXAMPLE_: * *An experiment results in the ability of bacteria to grow on a petri plate containing antibiotic* **NEGATIVE** Control: * Bacteria which do **NOT** carry a drug resistance marker should **NOT** be able to grow on a petri plate containing antibiotic ∴ if growth **IS** observed, it is a red flag that **something is WRONG** with the experiment! * *"What could be one reason for growth?"* * *​aka what could be a confounding variable here?*
113
Evaluating Research * Sources of Experimental Bias or Error * Define "**Selection** Bias"
**_Selection Bias_** The method used to *_select_* participants is **NOT** **_TRULY_** **RANDOM** * ∴ * the results are **not** representative of the **whole** population * There are "**systematic** **BASELINE differences"** among participants ....because **true** randomization was **not** achieved
114
Evaluating Research * Sources of Experimental Bias or Error Define "**Specific Real Area** Bias" * Give an example * Will having a **specific location** for a study *always* mean this type of bias will exist? * Give an example why/why not
**_SPECIFIC REAL AREA BIAS:_** * is bias introduced by conducting the study **in a specific area** that does **NOT** include a representative sampling *of the population being studied* _For example:_ * A study of U.S. eating habits (population= U.S. citizens) conducted **at the gym** leaves out all those who do **not** attend the gym—particularly bad because: * being a member of a gym is likely to **confound** with eating habits *Having a **specific** **location** for a study does **NOT** **always** mean "specific real area bias" will exist!* _For example:_ * a study investigating the drug-using habits of Maricopa County High School students (population=HS students) would **not** be biased if conducted **only** at the high school * because the **sample** would be **representative** of the population
115
Evaluating Research * Sources of Experimental Bias or Error Define "**Self-Selection** Bias" * What type of research shows *SIGNIFICANT* self-selection bias? * Give an example of SSB
**_Self-Selection bias_** * is bias introduced when participants in the study have the ability to: * **choose** to **participate** or **not to participate**, OR , * to **determine** their **level of involvement** ***Surveys** show significant self-selection bias* _For example:_ * Feedback boxes at fast-food establishments are **far** from representative of customer opinions * Generally because those with **negative** opinions have been shown to be far **more** **likely** to fill out such surveys * (as opposed to those with positive experiences)
116
Evaluating Research * Sources of Experimental Bias or Error Define "**Pre-Screening**," or "**Advertising** Bias" * Give an example wrt advertisements looking for volunteers for a study being done on **obesity**
**_Pre-Screening or Advertising Bias:_** * Occurs when the **screening** or **advertising** _***PROCESS*** ***ITSELF***_ results in * *...an **un**representative sample* _For example:_ * Advertisements asking for volunteers FOR THE **SAME** STUDY that are worded: * “Volunteers needed for an **obesity** study” OR * “Volunteers needed for a **weightloss** study” ...*will likely elicit **different volunteers*** (Obesity=BAD! Weightloss=GOOD!)
117
Evaluating Research * Sources of Experimental Bias or Error Define "**Exclusion** Bias" * Give an example
**_Exclusion Bias_** * Refers to the exclusion of an **entire** **group** from the population _Example:_ * A study about **childhood education** that does *not survey* any **homeschooled** children
118
Evaluating Research * Sources of Experimental Bias or Error Define "**Healthy User** Bias" * Give an example
**_Healthy User Bias_** * When the persons included in the study are likely to be **healthier** * ....than the ***general*** population _Example:_ * Studying cardiac **atherosclerosis** among participants in a **triathalon**
119
Evaluating Research * Sources of Experimental Bias or Error Define "**Berkson's Fallacy**" * How does it compare to *Healthy User Bias?*
**_Berkson’s Fallacy_** * Is the selection of participants from **hospitals**-- * **​**where the participants are likely to be **LESS** **healthy** than the general population Is the **OPPOSITE EFFECT** of the Healthy-User Bias
120
Evaluating Research * Sources of Experimental Bias or Error Define "**Overmatching**" * What happens if a *Confounding* variable is matched for? * What kind of study can Overmatching be **FATAL** in?
**_OVERmatching_** Matching on variables **other** than those that are risk factors for the disease under study * Is a **negative** outcome resulting from what is normally a **good** practice: * matching for **potentially confounding variables*** * i.e., age-matched _EXAMPLE_: * If you use **neighborhood controls** in a study on **NUTRITION** and **TUBERCULOSIS**... * You are inadvertedly matching for **SES** (and thus, **nutrition**)*
121
Evaluating Research * Sources of Experimental Bias or Error Define "**Observer** Bias" * Give an example using the Foot Study you're in
**_OBSERVER BIAS:_** Observers (or researchers) **KNOW THE GOALS** of the study or the hypotheses * *...and allow **this** knowledge to **INFLUENCE** their observations during the study* _Foot Study Example_: * We **want** statistically significant data, so we "observe" things in a way that will help us **get** statistically significant data
122
Evaluating Research * Sources of Experimental Bias or Error Define "**Demand Characteristics**" * Give an example using the Foot Study you're in
**_Demand Characteristics_** * **PARTICIPANTS** form an **interpretation** of the experiment's **purpose** * ...and unconsciously **change** their behavior* * to **FIT** that interpretation* _Example_: * During doming trials, we remark how subject's numbers were the "highest we've seen" * This makes them think we **WANT** to see higher numbers * They then strive to get the **highest numbers possible** *(In reality, we want NATURAL doming strengths)*
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Evaluating Research * Sources of Experimental Bias or Error Define "**Information** Bias" * This definition is split up into *2 different definitions--* * *​*depending on whether you're dealing with **Continuous** or **Categorical** Variables * What is it known by with **each** variable? * Give an example using the Foot Study you're in * For both Continuous **AND** categorical variables
**_Information Bias_** **=Wrong** or **inexact** recording of variables or data * With **CONTINUOUS** Variables (such as *blood pressure*): * this is referred to as _"**Measurement Error"**_ * With **CATEGORICAL** Variables (such as *tumor stage*): * this is known as **_"Misclassification"_** **​​**_Example_: * Continuous (measurements) * recording them wrong * Categorical (shoe size on form) * you put down the wrong shoe size for them
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Evaluating Research * Sources of Experimental Bias or Error Define a "**Confounding** Variable" * Give a hypothetical example of a confounding variable (using **Variable A,B**, and **C** where C is the confounding variable) * What is the "**Placebo** Effect?"
**_Confounding Variables_** (a.k.a. confounding factor, confounder) * An extraneous variable that **INFLUENCES** the variables being studied * *....but is **NOT** part of the **_expected_** correlation or causal pathway being investigated* _EXAMPLE_: * Suppose the relationship between A and B is being investigated * A is hypothesized to **increase** B * Experimental results **support** this hypothesis * It is **later** discovered that a **third** variable (i.e., **extraneous** variable) influences both A **and** B, * Decreasing A, and * Increasing B * In fact, it was C that **created** the observed result in B that was **originally** attributed to A ***Variable C is a confounding variable*** **_Placebo Effect:_** * One **example** of a confounding variable * The placebo effect occurs when participants given a placebo (i.e., sham treatment) during a study experience REAL or PERCEIVED health benefits-- * due to their belief that they ARE being treated
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Evaluating Research * Sources of Experimental Bias or Error Define a "**Detection** Bias" * Give an example
**_Detection Bias_** * Systematic **differences** **between** **groups...** * ...caused by _inconsistency_ in* * the **method of detection** or **diagnosis*** _EXAMPLE:_ * A study reports that inner city children suffer from ADHD at **twice** the rate of suburban children It is **later** discovered that systematic differences existed between: * **diagnostic tools,** and * **training available** * ...at **inner city** hospitals included in the study * ...vs. **suburban** hospitals included in the study * Basically, they're detecting ADHD rates *inconsistently,* because suburban hospitals are able to more accurately diagnose those who **REALLY** have ADHD * Inner city hospitals are quicker to just "slap a label" on 'em
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Evaluating Research Sources of Experimental Bias or Error Define "**Performance** Bias" * Give an example of this in a *hospital* scenario
**_Performance Bias_** * Systematic differences between groups... * in terms of the* ***_ACTUAL_ CARE OR TREATMENT PROVIDED*** _EXAMPLE_: * A physician *unconsciously* pays **closer** attention to and conducts **more** followup with patients the doctor **knows** to be enrolled in a heart study This results in differences in care for those individuals **not** accounted for in the study
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Evaluating Research * Sources of Experimental Bias or Error Define "Experimenter Bias," **a.k.a**., "\_\_\_\_\_\_\_ Bias" * What are the **2 types** of Experimenter Bias? Apart from those 2 types, what **else** could be considered "Experimenter Bias?"
**_Experimenter Bias_** (a.k.a., **Researcher** Bias) * ERRORS introduced into a study ***due to the expectations of the _investigator_*** * _2 Types:_ 1. **Confirmation** Bias 2. **Reporting** Bias Experimenter Bias also can include unconscious **communication of expected results** to the participants * ...thereby influencing their **behavior**
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Evaluating Research * Sources of Experimental Bias or Error **Experimenter** Bias (2 types) * Describe "**Confirmation** Bias"
**_Confirmation Bias:_** * The tendency to **favor** information that **confirms** one’s hypothesis or preconceived notions * and to **dismiss** information that **discredits** them (This sort of thing also happens *psychologically)*
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Evaluating Research * Sources of Experimental Bias or Error **Experimenter** Bias (2 types) * Describe "**Reporting** Bias"
**_Reporting Bias:_** * Systematic differences resulting from **some** findings being reported and **other** findings **NOT** being reported * Investigators may withhold or ignore data that **does not** support their hypothesis (if conscious and intentional this would be a clear violation of ethics) Statistically-significant results are usually **_far more likely to be reported_** than are statistically **in**significant results ...although **BOTH** are important to an ***unbiased*** determination
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Research Design & Execution * Measurement Compare **Accuracy** vs. **Precision**
**Accuracy** * is a measure of the degree to which a value represents the **true** or **correct** value **Precision** * is a measure of the degree to which repeatedly measured values show the **same** or **reproducible** values * The **greater** the range or **scatter** of measurements, the **less** precision
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Research Design & Execution * Measurement Compare **"****Reliability"**with**"****Validity"** * What results in **LOW** internal Validity?
**_RELIABILITY_** * Results are **consistent** and **repeatable** **_VALIDITY_** * The test or experiment measures what it **purports** to measure * ...and uses methods that **meet scientific standards** ***Failure** **to adhere** to the **standards of the scientific method** or other accepted experimental **best** **practices** _results in **LOW** internal validity_*
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Research Design & Execution * Measurement **Reliability** * Compare "**Test-Retest**" reliability with "**Inter-Rater**" reliability In **both** cases, a high value of reliability is around \_.\_ and shows good _____ \_\_\_\_\_\_
_**"Test-Retest"** reliability_ * is a measure of the degree of consistency between **one** administration of a test and a **subsequent** administration **of** **that same test** (i.e. the “retest”) _**"Inter-Rater"** reliability_ * is a **measure of consistency** between multiple raters or evaluators that are assigning the **same** values or making the **same** observations *In both cases, a high value of reliability is around **1.0** and shows good **internal validity***
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**DECREASING**"x" by a _factor of 4_ is the **same** as multiplying the variable (x) by?
**1/4x**
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**Pv=nRT** ## Footnote * If the volume goes **down** by **80%**, it has lost ___ of its value— * which is the same as being multiplied by\_\_\_ * or going down by a factor of \_
* If the volume goes down by 80%, it has lost **4/5** of its value— * which is the same as being multiplied by **1/5** * or going down by a factor of **5**
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To say that something is 225% **AS** dense as something else is to say that it is \_\_\_% **MORE** dense
125% Same as multiplying it by 5/4
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Correlation vs. Causation * Linear Regression Analysis **Correlation Coefficient, r2** * Describe how the correlation coefficient relates to **SCATTER PLOTS,** *aka Linear Regression Analysis* (shown below) * If the data points are **CLOSER**, as a whole, to the **TREND LINE:** * Will you have a **higher/lower r2** value?
* Correlation coefficients relate to linear regression analysis * A large number of trials * involving **changes** in the **independent** variable * are graphed against the **dependent** variable *resulting in a **SCATTER PLOT*** * A “**Least Squares**” or “**Best Fit**” line is drawn * that **best** approximates the **trend** of the data points _*The correlation coefficient, r2 is a measure of how tightly the **DATA** fit to **THIS** line!*_ The **CLOSER** the data are, as a whole, to the trend line: * the **HIGHER** the r2 value
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Correlation vs. Causation * Linear Regression Analysis **Correlation Coefficient, r2** * Correlation coefficients vary from __ to \_\_ * an r2 value of ___ would be a **PERFECT** correlation * The correlation coefficient is said to explain the **amount of variance** in __ **ACCOUNTED FOR** by \_\_
​Correlation Coefficients vary from **0 to 1** * An r2 value of **1.0** would be a **PERFECT** correlation! * The correlation coefficient is said to explain the amount of variance in **y** ACCOUNTED FOR by **x***
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Research Methods * Describe **HILL'S CRITERIA** * What are they used to **EVALUATE** in statistics? * List the **9 Criteria** * ​Which is considered to be the MOST IMPORTANT of the 9? *HINT: **T**he **C**razy **DR**agon **C**aleb **P**oops **T**he **Si**lly **S**tring **A**lways!*
*Hill’s Criteria is a **SET OF GUIDELINES** used to evaluate whether or not a **CAUSAL RELATIONSHIP** exists* 1. **T**emporality 2. **C**onsistency 3. **D**ose-**R**eponse Relationship 4. **C**oherence 5. **P**lausibility 6. **T**estable by Experiment 7. **S**pecificity 8. **S**trength 9. **A**nalogy
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Research Methods **HILL'S CRITERIA** * Describe "Temporality"
_Temporality:_ *In time, the exposure or treatment* ***MUST PRECEDE THE OUTCOME*** * If A **causes** B, A **must** occur in time **prior** to B _This is often considered the **most important** Hill Criteria_ * If the outcome is found to occur **before** the exposure in even a few cases, the potential of causality is generally **REJECTED**
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Research Methods **HILL'S CRITERIA** * Describe "Strength" * A larger ___ and _ -**value**, or a smaller _ -**value** ***​​....** would all **SUPPORT** causation*
_Strength_ * The **MAGNITUDE** of the **CORRELATION** or association * *including statistical measures of **significance*** A **larger** correlation, **larger** r2 value, or a **smaller p value** would all **support** causation
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Research Methods **HILL'S CRITERIA** * Describe "Consistency" * "The correlative relationship is \_\_\_\_\_\_\_\_\_\_"
**_Consistency:_** _The correlation or association:_ * continues across **MULTIPLE** trials, across time, or when the study is **REPLICATED** by others* * In other words, the relationship is **REPRODUCIBLE***
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Research Methods **HILL'S CRITERIA** * Describe "Specificity"
**_Specificity:_** *​One of the **weakest** Hill Criteria* * High specificity means the potential cause results in only **ONE** specific effect * If present, it can provide **additional** support for causation-- * but the lack of specificity is common in **MANY** established cause-effect relationships
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Research Methods **HILL'S CRITERIA** * Describe "Plausibility"
**_Plausibility:_** The association fits **LOGICALLY** within our current understanding of how a process works The association has a logical theoretical basis
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Research Methods **HILL'S CRITERIA** * Describe "Dose-Response Relationship" * *The observed _____ is proportional TO?* *_Does meeting this criteria determine **CAUSATION**?_*
**_Dose-Response Relationship:_** The observed **response** is **proportional to:** the **dosage** or **degree of the exposure** or **treatment** * This is considered **STRONG** evidence of causation* * ...but is **NOT** necessary*
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Research Methods **HILL'S CRITERIA** * Describe "Testable by Experiment" * What **IS** it that needs to be "testable?"
**_Testable by Experiment:_** The **_ASSOCIATION_** can be: ***REPROD******UCED VIA EXPERIMENT***
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Research Methods **HILL'S CRITERIA** * Describe "Coherence" * Association is compatible with...?
**_Coherence_**: The **ASSOCIATION** is **COMPATIBLE** with: *existing or previously-established science*
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Research Methods **HILL'S CRITERIA** * Describe "Analogy"
**SIMILAR associations** are **shown** or **known** to exist that are: ***analogous to** the* *association being considered*
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Research Methods * Define "**INTERNAL** Validity" * "The extent to which you are able to say that...?"* * What is internal validity a **function** of wrt the study itself?
**_Internal Validity_** The extent to which you are able to say that: No **OTHER** variables (except the one **you're** studying) caused the result ...which is a function of the scientific **RIGOR** of the study
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Research Methods * Differentiate b/t a **CONDITION** that is "**Necessary**" vs one that is merely "**Sufficient**"
**_Necessary:_** A condition that **MUST** be satisfied in order for an event to occur **_Sufficient:_** A condition that, *_if satisfied_*, **GUARANTEES** that an event **WILL** occur!
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Research Methods * Define "**EXTERNAL** Validity" * External Validity= \_\_\_\_\_\_\_\_\_\_\_bility* * What does external validity **DEPEND** heavily on? * Give an example of a study with POOR external validity
*External Validity* = ***GENERALIZABILITY!*** ## Footnote =The degree to which the findings can be **extrapolated** to the **general** population *_This depends a lot on:_* *the **SUBJECTS** being tested-- are the representative of the **general** population?* Example: * Sarah is a psychologist who teaches and does research at an expensive, private college.She's interested in studying whether offering specific praise after a task will boost people's self-esteem. If her hypothesis is correct, then giving someone a specific compliment on a job well done after a task will make them feel better about themselves. And if she can show that specific praise post-task boosts self-esteem, then managers at companies everywhere will be able to boost their employees' self-esteem by offering them specific praise.* * But here's a **problem**: the volunteers that Sarah gets for her study are **all college students**, most of them are **white**, and most of them are from **privileged backgrounds*** ***Sarah worries that her results might not be applicable to people who are NOT in their late teens or early 20s, white, and rich***
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Research Methods * Define a **SINGLE-BLIND** test * What all information gets witheld (3), and from whom?
_Information about:_ * The **study** itself * **Who** is in the... * Control groups * Treatment groups * other potentially **biasing** details _are concealed from:_ the person **DOING** the assessment
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Research Methods * Define a **DOUBLE-BLIND** test * What all information gets witheld (3), and from **whom**?
_Information about:_ * The **study** itself * **Who** is in the... * Control groups * Treatment groups * other potentially **biasing** details _are concealed from_ **BOTH:** 1. The **SUBJECT** 2. The person **DOING** the assessment (researcher)​ *
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Research Methods * **Type** I vs **Type II** Errors
**_Type I Error:_** ***REJECTED H0** but **SHOULDN'T HAVE*** **CLAIMED** difference between groups ...when **NONE** existed **_Type II Error_*****SHOULD** **HAVE** rejected H0 but **DIDN'T*** Did **NOT** claim a difference between groups ...when one **DID** exist
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Research Methods * Define the **NULL HYPOTHESIS, *H0*** * ​**What** is the Null hypothesis when testing for: 1. ​​Group differences 2. Correlation or Causation
**_The Null Hypothesis:_** H0 is always the ***LACK OF*** A RELATIONSHIP OR GROUP DIFFERENCE _In testing for **GROUP** **DIFFERENCES:**_ * **H**0 = there are ***NO*** *statistically significant differences* between groups _When testing for **CORRELATION** or **CAUSATION**:_ **H0**= there is ***NO* RELATIONSHIP**
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Research Methods * Define the **ALTERNATIVE HYPOTHESIS** * ​**What** is the Alt. Hypothesis when testing for: 1. ​​Group differences 2. Correlation or Causation
_The Alternative Hypothesis:_ The ***PRESENCE*** OF A RELATIONSHIP OR GROUP DIFFERENCE _The **OPPOSITE** of the_ **H0!** _In testing for **group** differences:_ * Alt. Hypothesis=there ***IS*** a difference between groups _When testing for **correlation** or **causation**:_ * Alt. Hypothesis= there ***IS*** a relationship.
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Statistics * Compare & Contrast **"Sample" vs. "Population"**
**Sample =** * that portion of a population included in the data * [e.g., U.S. veterans called in the phone survey] _**SMALLER** than the **POPULATION**_ *which is **ALL** the members in the group/category being sampled* [e.g., **ALL** U.S. veterans]
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Statistics * Define a **STATISTIC**
* A statistic is a **measure** or **data point*** * (such as **mean**, **median**, etc.)* * that is calculated for the sample* [e.g., **average income** among U.S. veterans in a sample]
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Statistics * Define "**Parameter**" * How does it compare with a **Statistic**?
**_Parameter =_** *a measure (such as mean, median, etc.) that is calculated for the **ENTIRE** population,* ***NOT** merely the sample of the population* [e.g., average income among **ALL** U.S. veterans]
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Statistics * Compare **Mean, Median, & Mode** * Also, define **Range**
**MEAN**= * the **average** value **MEDIAN** = * the **middle** of the data **MODE**= * the **most frequently occurring** data point **RANGE**= * the **minimum** data point ⇒**maximum** data point
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Statistics * Define **STANDARD DEVIATION (SD)** * What does a SMALL SD indicate? * What does a LARGE SD indicate?
**STANDARD DEVIATION** **(SD)** = * how tightly **associated** the data are **TO THE _MEAN_** _A small SD indicates:_ a **narrow** set of data for which most values are close to the mean _A large SD indicates:_ a **greater spread**, or **wider** distribution, of the data around the mean
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Standard Deviation (SD) * Define "**Normal Distribution**" * **1 SD**=\_\_% of the population * **2 SD**=\_\_% of the population * **3 SD**=\_\_% of the population
**_Normal Distribution=_** Hypothetical perfect ***BELL-SHAPED*** curve f_or which the following is true:_ * 1 SD = **68%** of the population * 2 SD = **95%** of the population * 3 SD = **99%** of the population
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Research Design When it comes to **Probability:** * The **ASSUMPTION** is that the **OUTCOMES** are _____ and _____ \_\_\_\_\_\_\_\_
***_Assumption = Outcomes are:_*** 1. **INDEPENDENT** * *Do **NOT** influence one another* 2. **MUTUALLY EXCLUSIVE** * *They **CANNOT** occur together*
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Probability * "And" vs. "Or" * To solve for each: * *"\_\_\_\_\_\_ the probabilities of individual events to get the overall probability of ____ events occurring"*
***_AND vs. OR_*** **AND =** * **MULTIPLY** *the probabilities of individual events to get the overall probability of* **BOTH** *events occurring* **OR =** * **ADD** *the probabilities of each individual event together to get the overall probability of* **EITHER** *event occurring*
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Hypothesis Testing * **t-test or z-test** * What is the **t-test** or **z-test** (once calculated) **COMPARED** to? * What does this comparison **give** us?
***t-Test or z-Test ⇒p value*** The “test statistic” (either a **t-value** or a **z-value**) is calculated * This result is **COMPARED** to: * a **TABLE** of t-values or z-values ***_The table gives us:_*** *the **SIGNIFICANCE LEVEL, "**α," associated with that test statistic*
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Hypothesis Testing * **t-test or z-test** * For a **z-test,**"**n**" (sample size) must be **GREATER THAN** what number? * Once this criteria is met, what can we assume about the **distribution**? * When would we have to use a **t-test?** * ​What does **THIS** mean wrt its distribution?
**z-test** * For a z-test, ***n\>30*** * *​This will mean it has a **NORMAL (BELL-SHAPED) DISTRIBUTION*** * We'd use a t-test when our **sample size is** ***SMALL*** * ​This will mean our graph will **NOT** be normally distributed (only approximately)
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Hypothesis Testing Significance Level, "α" * What are the 3 α values we'll see? _When comparing **p** and α values:_ * what does a **p value \> .005** indicate wrt **level of confidence?**
Significance Level (α) * α = **0.05, 0.01, 0.001*** * **p \< 0.05** means we can be **95% confident** that the results are actual/**real** * ...**RATHER** than the result of random chance* * **p \< 0.01** means we can be **99% confident**, and so forth