cos 0
1
cos 30
.9
cos 45
.7
cos 60
.5
cos 90
0
sin 0
0
sin 30
.5
sin 45
.7
sin 60
.9
sin 90
1

SI units:
 Femto
 Kilo
 Deci
 Femto
 Kilo
 Deci
Femto
 10^{15}
Kilo
 10^{3}
Deci
 10^{1}
SI Units:
 Mega
 Pico
 Hecto
10^{6}
10^{12}
10^{2}
SI Units:
 Tera
 Nano
 Centi
10^{12}
10^{9}
10^{2}
SI Units:
 Deca
 Giga
 Micro
 Milli
10^{1}
10^{9}
10^{6}
10^{3}
Convert 650 nm to SI units
650 x 10^{9}
Const. force (not velocity!) causes WHAT acceleration?
constant acceleration
When you throw a baseball, when is the only time it is accelerating?
Only when it is in contact with your hand
Increasing something by 25% is the same as multiplying it by what?
x 5/4
Define "mass"
the measure of an object's inertia
Define "inertia"
 the ability of an object to RESIST its change in velocity
Where on a mass/object is its "Center of Gravity?"
is at the center of the mass/object
Where is the "Center of buoyancy?"
 at center of mass of the FLUID displaced by the submerged object
Scalar or Vector?
Mass
scalar
Scalar or Vector?
temperature
scalar
Scalar or Vector?
velocity
vector
Scalar or Vector?
speed
scalar
Scalar or Vector?
displacement
vector
Scalar or Vector?
acceleration
vector
Scalar or Vector?
force
vector
Scalar or Vector?
work
scalar
Scalar or Vector?
energy
scalar
Scalar or Vector?
weight
vector
Scalar or Vector?
charge
scalar
Scalar or Vector?
electric field
vector
Scalar or Vector?
magnetic field, B
vector
Scalar or Vector?
time
scalar
Scalar or Vector?
momentum
vector
Scalar or Vector?
impulse
vector
Scalar or Vector?
density
scalar
Scalar or Vector?
torque
vector
What are the 4 questions that test conceptual understanding?
 Can I visualize it?
 Can I draw a picture/graph/diagram of it?
 Can i explain it to someone in layman's terms?
 Can i think of and describe reallife examples?
 Area of triangle
 formula=?
 formula=?
A_{tri}=1/2 bh
Vol of sphere formula
V_{sphere}=4/3 πr^{3}
SA of sphere formula
4pir^2
Manipulating equations mnemonics
SSISDDODIOSD
sqrt 2=
1.4
sqrt 3=
1.7
sqrt 2/2=
.7
sqrt 3/2=
.9
product of [H][OH] always equals:
1x10^14
Doppler effect formula
deltaf/fs=v/c
Be careful of S.N.E.W.L
Qualifiers (Write these down!) "StrengthensNot ExceptWeakensLeast"
tan0=
sin0/cos0
sin^2x+cos^2x=
1
11^2
121
12^2
144
13^2
169
14^2
196
15^2
225
Multiplying 2 vectors: If answer is scalar, (ie work), also mult by what?
cos0
multiplying 2 vectors: if answer is a 3rd vector (ie torque), also multiply by what?
sin0T=Frsin0
Decimal equivalent:1/5
.2
Decimal equivalent:1/8
.125
Decimal equivalent:1/9
.11
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)
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
When multiplying with scientific notation, what happens to the exponents?
You add them together
When dividing with scientific notation, what do you do with the exponents?
You subtract them
 Estimating Fractions
29/4 =?
=7.25
4 x 7=28
¼ is left behind

Estimating Square Roots

"High/Low" Method
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

Surface Area of a Sphere
 Formula=?
 Formula=?
SA_{sphere}= 4πr^{2}
 Trigonometry

All of the angles in any triangle must add up to?
 All of the angles in any triangle must add up to?
180°
Trigonomic Relationships
 sinθ=
 cosθ=
 tanθ=
sinθ=Opp/Hyp
cosθ=Adj/Hyp
tanθ=Opp/Adj
"SOHCAHTOA"
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°
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
Trigonomic Relations
 What are the INVERSES of sin, cos, and tan?
 sin^{1}
 cosecant
 cos^{1}
 secant
 tan^{1}
 cotangent
 cosecant
 secant
 cotangent
Trigonomic Relationships
 tanθ= ?
tanθ=sinθ / cosθ
Linear & NonLinear Graphs
 What does a graph look like for:
y=x
Linear & NonLinear Graphs
 What does a graph look like for:
y = 1/x
Linear & NonLinear Graphs
 What does a graph look like for:
y=x^{2}
Linear & NonLinear Graphs
 What does a graph look like for:
y = x
(Absolute Value)
Linear & NonLinear Graphs
 What does a graph look like for:
y = x^{3}
^{(Cubic)}
Linear & NonLinear Graphs
 What does a graph look like for:
y = √x
Linear & NonLinear Graphs
 What does a graph look like for:
y= ^{3}√x
(Cube Root)
Linear & NonLinear Graphs
 What does a graph look like for:
y = ln x
(Logarithmic)
How does it look different than y= logx?
Linear & NonLinear Graphs
 What does a graph look like for:
y = sinx
Linear & NonLinear Graphs
 What does a graph look like for:
y = cosx
Linear & NonLinear Graphs
 What does a graph look like for:
y = a^{x }
^{(Exponential)}
Linear & NonLinear Graphs
 What does a graph look like for:
y = 1/x
(Reciprocal)
Linear & NonLinear Graphs
 For the equation X= ½at^{2}
 Which of the following relationships will be LINEAR?
 Which will be NONLINEAR?
 X vs. t (or t vs. X)
 X vs. a (or a vs. X)
 a vs. t (or t vs. a)
X=½at^{2}
 NONlinear
 Linear
 NONlinear
Linear & NonLinear Graphs
What does a graph look like for:
y = tan x
Graphs used as Answer Choices
 If a variable is changing exponentially, will be linear or nonlinear on:
 a semilog graph?
 a loglog graph?
The log of an exponential function becomes linear, so exponential functions graphed on semilog axes end up being linear
 ...AND a linear function would be nonlinear
If the exponential function is graphed on loglog axes, the function will be nonlinear
The table below may be helpful
 The semilog graph described is for a linear Xaxis and a logarithmic Yaxis (loglin type not linlog)
Graphs used as Answer Choices
 Describe:
 a semilog graph
 A semilog graph has a logarithmic scale on one axis, but a linear scale on the other axis
Graphs used as Answer Choices
 Describe:
 a loglog graph
A loglog graph has a logarithmic scale on BOTH axes
Manipulating Equations
ay=vx^{2}/cq
 How are a and y related to each other?
inversely
Manipulating Equations
ay=vx^{2}/cq
How are x and q related to each other?
directly
Manipulating Equations
ay=vx^{2}/cq
How are a and q related to each other?
directly
Manipulating Equations
ay=vx^{2}/cq
How are a and c related to each other?
inversely
Manipulating Equations
X=½at^{2}
What will happen to time if the distance (x) is tripled?
x∝t^{2}
 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
√3=
1.7
Welldesigned research must have a hypothesis that is....?
a Testable hypothesis
 basically, it can be used to verify a clear YES or NO answer
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...?
 What kind of environment is it conducted in?
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
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 lowsodium diet required by the study guidelines
 This was thought to influence blood pressure measurements in those patients
 However, it is later discovered that all participants did not follow the strict lowsodium diet required by the study guidelines
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)
 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)
Human Subjects Research
 Describe "Observational" Research
 Investigator _______ data WITHOUT....? (2)
 Investigator observes data WITHOUT:

Direct control over the variables, OR
 Implementation of interventions
 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)
Medical Ethics
 Describe (in general) "Beneficence"
 One important aspect of this is ending a study because of...?
DO GOOD.
 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 longterm 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
Medical Ethics
 Describe (in general) "Nonmaleficence"
 One important aspect of this is ending a study because of...?
DO NO HARM
 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.
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)
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.
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 nonsmokers (Cohort B)
 A statistically significant correlation (r = 0.84, p < 0.01) exists between socioeconomic status and frequency of preterm 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
Observational Research Study Types
 Describe a "CrossSectional Study"
 Give some examples
CrossSectional 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.
Observational Research Study Types
 Describe a "CaseControl Study"
 By design, a CaseControl Study is always ________
 Give an example
CaseControl Study
By design, a CaseControl 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 CaseControl Study is the one is the study that linked lung cancer to smoking
EXAMPLE:

There is a suspicion that zinc oxide (the white nonabsorbent sunscreen traditionally worn by lifeguards) is more effective at preventing sunburns that lead to skin cancer than absorbent sunscreen lotions

A casecontrol 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
Observational Research Study Types
 What are some Pros & Cons of:
 CrossSectional Studies
Observational Research Study Types
 What are some Pros & Cons of:
 COHORT Studies
Observational Research Study Types
 What are some Pros & Cons of:
 CaseControl Studies
Also:
What kind of outcome are these studies useful for?
Useful for RARE outcomes
Observational Research Study Types
 Differentiate b/t:
Prospective & Retrospective Cohort Studies
 What's going on wrt the Exposure & Outcome?
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?
 For each:
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 Xaxis
DEPENDENT VARIABLE
 The variable MEASURED
 ....as a response to changes in the INdependent variable
 Also called the “outcome variable”
It can be thought of as the “EFFECT”
 You can't "Add" a Dependent Variable
 i.e., you can "add" an outcome...you can only "add" something that will change the outcome
 Always goes on the Yaxis
Independent vs. Dependent variables
 Identify the independent and dependent variables in the following scenarios:
 Time spent studying and test score
 Gas mileage and octane rating of the gas used
 Dosage of medication used and lab rat survival rate
 Level of aggression and amount of exposure to violent video games
 Independent: Time Spent studying
 Dependent: Test score
 Independent: Octane rating of gas
 Dependent: Gas mileage
 Independent: Dosage of medication
 Dependent: Survival Rate
 Independent: Exposure to violent VG's
 Dependent: Lvl of aggression
 Dependent: Test score
 Dependent: Gas mileage
 Dependent: Survival Rate
 Dependent: Lvl of aggression
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!!
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
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=?)
 What purpose do they serve in an experimental study?
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?
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
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
 Will having a specific location for a study always mean this type of bias will exist?
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 drugusing 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
Evaluating Research
 Sources of Experimental Bias or Error
Define "SelfSelection Bias"
 What type of research shows SIGNIFICANT selfselection bias?
 Give an example of SSB
SelfSelection 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 selfselection bias
For example:
 Feedback boxes at fastfood 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)
 Generally because those with negative opinions have been shown to be far more likely to fill out such surveys
Evaluating Research
 Sources of Experimental Bias or Error
Define "PreScreening," or "Advertising Bias"
 Give an example wrt advertisements looking for volunteers for a study being done on obesity
PreScreening or Advertising Bias:
 Occurs when the screening or advertising PROCESS ITSELF results in
 ...an unrepresentative 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!)
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
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
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 HealthyUser Bias
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., agematched
EXAMPLE:
 If you use neighborhood controls in a study on NUTRITION and TUBERCULOSIS...
You are inadvertedly matching for SES (and thus, nutrition)
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
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)
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?

depending on whether you're dealing with Continuous or Categorical Variables
 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
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
 A is hypothesized to increase B
 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

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
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
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:
 Confirmation Bias
 Reporting Bias
Experimenter Bias also can include unconscious communication of expected results to the participants
 ...thereby influencing their behavior
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)
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)
Statisticallysignificant results are usually far more likely to be reported than are statistically insignificant results
...although BOTH are important to
an unbiased determination
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
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
Research Design & Execution
 Measurement
Reliability
 Compare "TestRetest" reliability with "InterRater" reliability
In both cases, a high value of reliability is around _._ and shows good _____ ______
"TestRetest" 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”)
"InterRater" 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
DECREASING "x" by a factor of 4 is the same as multiplying the variable (x) by?
1/4x
Pv=nRT

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
 which is the same as being multiplied by 1/5
 or going down by a factor of 5
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
Correlation vs. Causation
 Linear Regression Analysis
Correlation Coefficient, r^{2}
 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 r^{2} 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
 involving changes in the independent 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, r^{2} 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 r^{2} value
Correlation vs. Causation
 Linear Regression Analysis
Correlation Coefficient, r^{2}
 Correlation coefficients vary from __ to __
 an r^{2} 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 r^{2} 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
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: The Crazy DRagon Caleb Poops The Silly String Always!
Hill’s Criteria is a SET OF GUIDELINES used to evaluate whether or not a CAUSAL RELATIONSHIP exists
 Temporality
 Consistency
 DoseReponse Relationship
 Coherence
 Plausibility
 Testable by Experiment
 Specificity
 Strength
 Analogy
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
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 r^{2} value, or a smaller p value would all support causation
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
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 causeeffect relationships
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
Research Methods
HILL'S CRITERIA
 Describe "DoseResponse Relationship"
 The observed _____ is proportional TO?
Does meeting this criteria determine CAUSATION?
DoseResponse 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
Research Methods
HILL'S CRITERIA
 Describe "Testable by Experiment"
 What IS it that needs to be "testable?"
Testable by Experiment:
The ASSOCIATION can be:
REPRODUCED VIA EXPERIMENT
Research Methods
HILL'S CRITERIA
 Describe "Coherence"
 Association is compatible with...?
Coherence:
The ASSOCIATION is COMPATIBLE with:
existing or previouslyestablished science
Research Methods
HILL'S CRITERIA
 Describe "Analogy"
SIMILAR associations are shown
or known to exist that are:
analogous to the
association being considered
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
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!
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!
=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 selfesteem. 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 posttask boosts selfesteem, then managers at companies everywhere will be able to boost their employees' selfesteem 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
Research Methods
 Define a SINGLEBLIND 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
Research Methods
 Define a DOUBLEBLIND 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:

The SUBJECT

The person DOING the assessment (researcher)
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
Research Methods
 Define the NULL HYPOTHESIS, H_{0}

What is the Null hypothesis when testing for:
 Group differences
 Correlation or Causation

What is the Null hypothesis when testing for:
The Null Hypothesis:
H_{0} 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:
H_{0}= there is NO RELATIONSHIP
Research Methods
 Define the ALTERNATIVE HYPOTHESIS

What is the Alt. Hypothesis when testing for:
 Group differences
 Correlation or Causation

What is the Alt. Hypothesis when testing for:
The Alternative Hypothesis:
The PRESENCE OF A RELATIONSHIP OR GROUP DIFFERENCE
The OPPOSITE of the H_{0}!
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.
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]
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]
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]
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
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
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 BELLSHAPED curve for which the following is true:
 1 SD = 68% of the population
 2 SD = 95% of the population
 3 SD = 99% of the population
Research Design
When it comes to Probability:
 The ASSUMPTION is that the OUTCOMES are _____ and _____ ________
Assumption = Outcomes are:

INDEPENDENT
 Do NOT influence one another

MUTUALLY EXCLUSIVE
 They CANNOT occur together
Probability
 "And" vs. "Or"
 To solve for each:

"______ the probabilities of individual events to get the overall probability of ____ events occurring"

 To solve for each:
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
Hypothesis Testing

ttest or ztest
 What is the ttest or ztest (once calculated) COMPARED to?
 What does this comparison give us?
 What is the ttest or ztest (once calculated) COMPARED to?
tTest or zTest ⇒p value
The “test statistic” (either a tvalue or a zvalue) is calculated
 This result is COMPARED to:
 a TABLE of tvalues or zvalues
The table gives us:
the SIGNIFICANCE LEVEL, "α," associated with that test statistic
Hypothesis Testing

ttest or ztest
 For a ztest, "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 ttest?
 What does THIS mean wrt its distribution?
 For a ztest, "n" (sample size) must be GREATER THAN what number?
ztest

For a ztest, n>30
 This will mean it has a NORMAL (BELLSHAPED) DISTRIBUTION
 We'd use a ttest when our sample size is SMALL
 This will mean our graph will NOT be normally distributed (only approximately)
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