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STATEY-STAT-STAT > THE FINAL EXAM PREP. > Flashcards

THE FINAL EXAM PREP. Flashcards

1
Q

What does a nominal scale mean?

A

Providing an object with a numerical value (like a label). It does NOT give it value, only representation (i.e. number on a soccer player’s jersey)

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2
Q

What is a discrete variable?

A

When a variable can only take on a few specific options.

i.e. Men/women, Tall/short, Young/old, Black/white/tan, etc.

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3
Q

What is a ratio scale?

A

It has a TRUE ZERO point that represents the absence of something and is a means of measuring two or more things to one another. 30cm is twice as long as 15cm, which is 4 times shorter than 60cm (15 x4 = 60)

ITS COMPARATIVE

i.e. Height (You can be 5”6, but not 0”0; a person weighing 150 lbs is half the size of a fat person who is 300 lbs).

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4
Q

What is an ordinal scale?

A

A scale that places things in a ranked order. (Fattest to skinniest, smartest to dumbest).

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5
Q

What is an interval scale? What makes it different from a ratio scale?

A

A system that identifies differences between two points that has no ABSOLUTE zero. Differences are equal no matter where they fall in the numerical system (i.e. -10 to -20 degrees is the same difference of 65 - 55 degrees)

The difference is Ratio scales cannot be less than Zero. You cannot have -5 pies (ratio), whereas you can be -6 under par in golf (Interval)

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6
Q

What is a continuous variable?

A

When a variable has virtually limitless numerical values (Speed, grains of sand, etc).

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7
Q

What does the symbol Σ (Sigma) mean? what does Σx mean?

A

Add

Σx = add all values

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8
Q

Differentiate between probability and non-probability sampling

A

Probability Sampling:

Every person in the population has an equal chance of being selected for the experiment

Non-probability Sampling:

Selecting methods in which the selection of participants are not random and participants in a population do NOT have equal chance of being selected.

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9
Q

What is Simple random sampling versus stratified random sampling?

A

Simple = Taking EVERY person in a population and randomly selecting people

Stratified = separating population into subgroups and taking random people from those subgroups

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10
Q

What is the difference between Convenience, purposive, and quota sampling?

A

Convenience = People are selected because they are convenient and available

Purposive = Seeking out people who meet specific criteria for the test (smokers, pregnant women, Doctors, etc).

Quota = Intentionally selecting specific proportion of a subgroup within a population (Muslims living in Toronto)

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11
Q

What is the standard error?

A

The standard deviation of a sampling distribution. How wide or narrow the results appear once plotted.

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12
Q

What is a confidence interval?

A

The probability of a finding occurring in repeated tests (60% of the time it works everytime)

95% of the results confirm the hypothesis

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13
Q

What is a related sample? What are the pros and cons of using a related sample?

A

An experimental design that utilizes a participant more than once; by the means of being observed multiple times throughout the study with more than one treatment.

i.e. completing a test in the morning vs at night

Pros:

  1. Less variability from person-to-person
  2. More control over extraneous variables
  3. Fewer participants needed for test

Cons:

  1. Order effect - the effect in which tests are done may effect overall performance later on
  2. Carry-over effect - the previous tests resulting in a change of scores in subsequent tests due to experience.
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14
Q

What is a matched Sample?

A

Pairing two participants who are very similar together and recording one of them with the treatment option and the other as the control

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15
Q 
A study was completed that tested students writing exams and their levels of stress. 95% of the students reported stress levels above a 3 out of 10 or higher. This represents which of the following?
A/ Order effect
B/ Confidence interval
C/ Sampling Error
D/ Discrete Variable
A

B/ Confidence interval, because it states the probability of a specific finding based upon testing and the likelihood of the test repeating itself in future testing (95%)

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16
Q 
Researchers want to compare the net income of Christians living in Brampton, Ontario. For their research selection, they decided to seek out Christian families with 2 adults living in the household. Which of the following did they implement?
A/ Convenience sampling
B/ Stratified Random Sampling
C/ Quota Sampling
D/ Purposive Sampling
A

C/ Quota sampling

because they are seeking a specific subgroup within a population.

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17
Q 
Researchers what to test the opinions of Donald Trump. They decide to walk to a near-by mall on a Tuesday night and randomly ask people leaving the shopping centre their opinions. This is an example of:
A/ Purposive sampling
B/ Convenience Sampling
C/ Simple random Sampling
D/ Stratified random Sampling
A

B/ Convenience Sampling

They went to somewhere close and went to people who are easy to reach

It is neither simple or stratified because they are not completely random within the population. Not everyone goes to the mall on a Tuesday night.

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18
Q 
Researchers want to test the variability of speeds among Subaru and Mitsubishi cars on a straight racetrack. The researchers use  \_\_\_\_ variables.
A/ Continuous
B/ Discrete
C/ Ratio
D/ Nominal
A

A/ Continuous

Speed ranges from 0 - limitless (although it is a car…)

Discrete only provides a few options (0km, 5km, 120km, 245km)

Ratio and nominal wouldn’t make sense if you want to calculate SPECIFIC speeds and compare the two.

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19
Q 
Researchers place people in rank based upon their weight. This is a form of \_\_\_\_\_\_.
A/ Nominal Scale
B/ Ordinal Scale
C/ Interval Scale
D/ Ratio Scale
E/ discrimination
A

A/ Ordinal Scale

A continuum/rank that measures from one end of a spectrum to another

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20
Q 
Researchers want to test the hand-size of dentists working in ontario. Which type of sampling selection would they use?
A/ Convenience sampling
B/ Simple Random Sampling
C/ Quota Sampling
D/ Purposive Sampling
A

D/ Purposive Sampling

(Specific criteria are needed; only Dentists).

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21
Q 
A researcher concludes that Eating Chicken wings will not make you fat; however, repeated tests has shown that he was incorrect. This is an example of:
A/ Null Hypothesis
B/ Alternative Hypothesis
C/ Type I error
D/ Type II error
A

D/ Type II error

The null hypothesis states that there is NO relation between wings and obesity… The Null is false, and you failed to reject it. This is a type II error

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22
Q

What is a Type I error?

A

Rejecting the Null hypothesis, when in fact the Null hypothesis is correct.

(When you believe there is a relationship going in, when in fact there is no relationship between the variables).

i.e. Believing that driving a SUV makes you a safer driver, when in fact there is Ø evidence to support that hypothesis. You failed to accept the null.

23
Q

You ask a questionnaire to identify the amount of anxiety in patient’s in both the pre-op and post-op stages. You ask them before they head into surgery to rate their anxiety levels, and then afterwards. Then once both scores are taken, you subtract them from one another. What is this known as?

A

Difference score

X1 - X2 = diff score

i.e. - Anxiety 6 (pre-op) - 1 (post-op)
6-1 = 5

24
Q

Kurt is doing a study that examines his ability to focus with and without coffee. During testing, he completes a puzzle while sober, and one while drinking coffee. You notice a significant difference in his score on the second-time around. You suspect this could be _____ effect.

A

Carry-over effect

When previous experience during testing affects future scores and skews the results.

25
Q

Differentiate between a one-tailed test and a two-tailed test.

A

One-tailed - A test that will reject extreme outcomes in one specific tail of the test (Very positively or negatively displaced results from the mean).

Two tailed - Rejects extreme scores from either side of the mean (both positively and negatively skewed scores.

26
Q

What does the Central Limit Theorem state?

A

A normal distribution will appear as the sample size increases. Regardless of the shape of the population distribution.

27
Q

What does variability mean?

A

The degree to which data points are situated around the mean (i.e. wide, narrow, scattered, etc).

28
Q

What is the Interquartile Range?

A

The 50% range of data scores that fall within 50% of the mean comparative to the other scores. 25% below the mean and the 25% above the mean.

29
Q 
This is the measure of how far a set of scores are spread out in a distribution.
A/ Range
B/ Sample Variance
C/ Variance
D/ Standard Deviation
A

B/ Sample variance

30
Q

What are degrees of freedom?

A

Determines the amount of deviations each score is from the mean. Done by subtracting the score from the mean (i.e. score of 6 and a mean of 4 = 4-6 = -2

31
Q

What is the rejection level in a hypothesis?

A

The probability in which we will reject the Null hypothesis; by finding data that suggestions a relationship. The rejection level sets parameters in place that identify a correlation

32
Q

What is Alpha or Significance level?

A

The probability of a type I error occurring

(Probability of of thinking there is something going on, when there is nothing going on).

33
Q 
\_\_\_\_ Is best defined as: "The standard deviation of the sampling distribution of a statistic"
A/ Standard Error
B/ Sampling Distribution
C/ t Distribution
D/ Sample Error
A

A/ Standard Error

34
Q

When you complete multiple tests on the same population and compare their means to one another you are completing a:
A/ Sampling Error
B/ Sample Distribution
C/ Sampling distribution of the difference between means
D/ Standard error of the difference of the means

A

C/

35
Q

What is pooled variance best defined as?

A

A method of estimating variance among difference populations when the mean of each population may be different, but there variance may be the same.

pop 1: mean = 6 variance = 3.54
pop 2: mean = 4 variance = 3.54
pop 2: mean = 9 variance = 3.54

36
Q

What is a dichotomous variable?

A

A variable that can only have two values (gender is a good example)

37
Q 
Researchers asked an opinionated question to both men and women. To which they either responded yes or no. They made a chart which had a column for men and women, and another column for yes and no. This is an example of a:
A/ Phi test
B/ Dichotomous variable
C/ Chi-squared Test
D/ math
A

A/ Phi test - because it is testing a correlation between men and women and their responses… all of which are dichotomous (only two options: male/female, yes/no)

38
Q

What is a Chi-Squared test?

A

A test used to determine is what is observed matches up with what is expected.

If you look at dice, they have 6 sides; all of which have an equal chance of being rolled (Expected that each side has an equal chance of being rolled).

BUT

You may observe that 5 is rolled more than 3 and 2 is rolled less than 6. Chi-Squared tests determine if what you observed can be accepted as truth or not.

39
Q

What does a critical value in a Chi-squared test represent?

A

The point at which you can accept or reject the null hypothesis.

40
Q

What does covariance mean?

A

The degree to which two variables change together. Represented by a number.

i.e. Bill and Hank take an IQ test in the morning and then in the evening. Covariance would look to see if both their scores changed equivalently.

41
Q

What does Pearson’s Correlation coefficient signify?

A

The direction and strength of a relationship between data.

42
Q

A positively skewed distribution has a tail stretching out to the ____.

A

Right

43
Q

What is a good percentage to trim from the ends of samples?

A

10%-20% from each end

44
Q

A ___ represents the number of deviations above or below the mean.

A

Z score

45
Q

What does the term “The 32nd percentile” mean in statistics?

A

The point below which 32% of the distribution falls. 32% of the data points fall within this range

46
Q

What is a type II error?

A

Refers to rejecting the null hypothesis when the null hypothesis is actually true.

ex. Null hypothesis = there is no relationship between show size and penis size.

Type II error would mean you believe there is a correlation between shoe and penis size, when in fact there isn’t. You should have agreed with the Null

47
Q

True or False…

A correlation of -0.81 is significantly lower than a correlation of 0.81

A

False. They are the same, the positive and negative only describes their relationship direction on the graph

48
Q

We would use a two-tailed test of r if ___.

A

We wanted to reject the null if the sample correlation was too positive or too negative.

49
Q

Why do we care about the standard error of a statistic?

A

It tells us how much the variables change over repeated tests.

50
Q

What does Cohen’s d represent/measure?

A

The difference between the sample size’s mean and the population’s mean expressed in standard deviations.

51
Q

What does a value of d=0.95 mean?

A

There is a difference of 0.95 standard deviation units between two means.

(Two means are ALMOST 1 standard deviation away from one another).

52
Q

What is a carry-over effect?

A

A situation were something about the first measurement influences the second measurement.

Ex. Learning the task in the first measurement may effect the second task.

53
Q

What do we mean by pooled-variance?

A

A method for estimated the variances of several different populations when the mean of each population may be different.

STATEY-STAT-STAT (4 decks)

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