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Stats - Research and Design > MCQ > Flashcards

MCQ Flashcards

1
Q

If SD is 5, the variance is what?

A

25

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2
Q

Positive kurtosis (leptokurtic) indicates what?

A

Scores are tightly clustered around the centre of the distribution

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3
Q

mean = 28, SD = 3, the z-score for a score of 34 is what?

A

2

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4
Q

An assumption for a one way repeated measures ANOVA but not a one way independent ANOVA

A

Sphericity

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5
Q

a p-value of 0.002 tells you what?

A

The probability of getting this result by chance is 0.2%, assuming the null hypothesis is correct

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6
Q

out of the following, which is the most appropriate reason to use a non-parametric test?:
A When the DV is measured on an ordinal scale
B When you have unequal sample sizes between conditions of the IV
C When the sample size is small
D When you have a violation of the assumption of homogeneity of variance

A

A

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7
Q

The following are all commonly stated assumptions/requirements for using ANOVA. Which of the 4 is the only one that the procedure always requires?
A Subjects are assigned to treatment conditions / groups using random allocation
B Data is from a normally distributed population
C DV is continuous (interval or ratio)
D Variance in each experimental condition is similar (assumption of homogeneity of variance)

A

C

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8
Q

A researcher runs a single t test and obtains a p value of p = .04. The researcher rejects the null hypothesis and concludes that there is a significant effect of the experimental manipulation in the population. What error or errors have they possibly made?

A

The researcher may have made a type 1 error

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9
Q

99% of z-scores lie between what:

A

+/- 2.58

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10
Q

If predictor X shows a correlation coefficient of -.45 with outcome Y, we can confidently say that:
A X is a significant predictor of Y
B Variance in X accounts for 20.25% (that’s -.45²) of the variance in Y
C X has a causal relationship with Y
D All of the above

A

B

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11
Q

How much variance has been explained by a correlation of r = .50?

A

25%

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12
Q

The relationship between two variables partialling out the effect that a third variable has on both of those variables can be expressed using what?

A

Partial correlation

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13
Q

A regression model in which variables are entered into the model on the basis of a mathematical criterion is known as a:

A

Stepwise regression

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14
Q

In multiple regression, a high VIF statistic, a low tolerance statistic, and substantial correlations between predictor variables, ALL indicate what?

A

Multicollinearity

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15
Q

In a multiple regression model, the t test statistic can be used to test?

A

The significance of the regression coefficients for each predictor

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16
Q

A Mixed ANOVA design would be appropriate for which of the following situations?

A Different participants are tested in each condition
B All participants are tested in all conditions
C Participants are tested in all conditions for at least one IV, and different participants are tested in each condition for at least one IV
D None of the above

A

C

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17
Q

In a one-way independent ANOVA with 40 participants and 5 conditions of the IV, what are the degrees of freedom for the between-groups Mean Squares (MSbetween)?

A

4

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18
Q

How many IV’s and DV’s are there in a two-way ANOVA

A

Two IV, 1 DV

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19
Q

In a two-way factorial design, the SSR (residual sum of squares) consists of what?

A

Variance which cannot be explained by the independent variables

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20
Q

What is the non-parametric equivalent of a one-way repeated measures ANOVA?

A

Friedman Test

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21
Q

What is a limitation of the Chi-square test?

A

A It cannot be used when you have more than 2 categorical variables
B Directional hypotheses are not possible when you have more than two conditions of a variable
C A small sample size can result in an unreliable test statistic

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22
Q

Are directional hypotheses possible with chi-square?

A

Yes, but ONLY when you have a 2x2 design

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23
Q

What is the difference between a loglinear model and a chi-square test?

A

loglinear is an extension of chi-square test,
LL models can determine complex interactions in multidimensional contingency tables with more than two categorical variables whereas a chi can only analyse two variables at a time

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24
Q

When conducting a loglinear analysis, if our model is a good fit of the data then goodness-of-fit statistic for the final model should be what?

A

non-significant (p = >0.05)

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25
Q

Example:
An organizational psychologist is hired as a consultant by a person planning to open a coffee house for college students. The coffee house owner wants to know if her customers will drink more coffee depending on the ambience of the coffee house. To test this, the psychologist sets up three similar rooms, each with its own theme (Tropical; Old Library; or New York Café ) then arranges to have thirty students spend an afternoon in each room while being allowed to drink all the coffee they like. (The order in which they sit in the rooms is counterbalanced.) The amount each participant drinks is recorded for each of the three themes.

  1. Independent variable(s)
  2. Is there more than 1 IV?
  3. The levels the independent variable(s)
  4. Dependent variable
  5. Between (BS) or within-subjects (WS)?
  6. What type of design is being used?
A
  1. Theme
  2. No
  3. Tropical, old library, new york cafe
  4. Amount of coffee consumed
  5. Within
  6. 1-way repeated measures
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26
Q

A manager at a retail store in the mall wants to increase profit. The manager wants to see if the store’s layout (one main circular path vs. a grid system of paths) influences how much money is spent depending on whether there is a sale. The belief is that when there is a sale customers like a grid layout, while customers prefer a circular layout when there is no sale. Over two days the manager alternates the store layout, and has the same group of customers come each day. Based on random assignment, half of the customers told there is a sale (20 % will be taken off the final purchases), while the other half is told there is no sale. At the end of each day, the manager calculates the profit.
1. Independent variable(s)
2. Is there more than 1 IV?
3. The levels the independent variable(s)
4. Dependent variable
5. Between (BS) or within-subjects (WS)?
6. What type of design is being used?

A
  1. Sale/No Sale, Store’s layout
  2. Yes
  3. Sale vs No Sale, Grid vs Circular
  4. Profit
  5. BS (Sale) and WS (Layout)
  6. 2-way mixed measures
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27
Q

A researcher at a drug treatment center wanted to determine the best combination of treatments that would lead to more substance free days. This researcher believed there were two key factors in helping drug addiction: type of treatment and type of counseling. The researcher was interested in either residential or outpatient treatment programs; and either cognitive-behavioral, psychodynamic, or client-centered counseling approaches. As new clients enrolled at the center they were randomly assigned to one of six experimental groups. After 3 months of treatment, each client’s symptoms were measured.
1. Independent variable(s)
2. Is there more than 1 IV?
3. The levels the independent variable(s)
4. Dependent variable
5. Between (BS) or within-subjects (WS)?
6. What type of design is being used?

A
  1. Type of treatment, type of counseling
  2. Yes
  3. Residential or outpatient/cb, psychodynamic or client centered
  4. Substance free days
  5. BS
  6. 2 way independent measures ANOVA
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28
Q

The researcher hypothesized that there would be an interaction between dog breed (Collie or German Shepherd) and week of obedience school training (all dogs measured at 1 week and 5 weeks) as they relate to the number of times the dog growls per week. Specifically, it was hypothesized that Collies would show no difference in growls between 1 week and 5 weeks, but German Shepherds would growl less at 5 weeks than at 1 week.
1. Independent variable(s)
2. Is there more than 1 IV?
3. The levels the independent variable(s)
4. Dependent variable
5. Between(BS) or within-subjects (WS)?
6. What type of design is being used?

A
  1. Dog breed and measurement time
  2. Yes
  3. Collie-German Shepherd/Week 1-Week 5
  4. Number of growls
  5. Dog breed - BS, Measurement time - WS
  6. 2 way mixed ANOVA
29
Q

What is the F-Ratio?

A

A stat that tells us whether the model fitted to the data accounts for more variation than extraneous factors.
It does NOT tells us where the differences are

30
Q

What are the rules of contrast coding?

A

Rule 1: Groups coded with positive weights compared to groups coded with negative weights.
Rule 2: The sum of weights for a comparison should be zero.
Rule 3: For a given contrast, the weights assigned to the group(s) in one chunk of variation should be equal to the number of groups in the opposite chunk of variation.
Rule 4: If a group is not involved in a comparison, assign it a weight of zero
Rule 5: If a group is singled out in a comparison, then that group should not be used in any subsequent contrasts.

31
Q

When conducting a Repeated-Measures ANOVA, which of the following assumptions is NOT relevant?
A. Independent residuals
B.Homogeneity of variance
C. Sphericity
D. They are all relevant

A

B

32
Q

One advantage of repeated measures designs over independent designs is that we are able to calculate a degree of error for each effect, whereas in an independent design we are able to calculate only one degree of error: true or false?

A

True

33
Q

An experiment was done to look at the positive arousing effects of imagery on different people. A sample of statistics lecturers was compared against a group of students. Both groups received presentations of positive images (e.g., cats and bunnies), neutral images (e.g., duvets and light bulbs), and negative images (e.g., corpses and vivisection photographs). Positive arousal was measured physiologically (high values indicate positive arousal) both before and after each batch of images. The order in which participants saw the batches of positive, neutral and negative images was randomized to avoid order effects. It was hypothesized that positive images would increase positive arousal, negative images would reduce positive arousal and that neutral images would have no effect. Differences between the subject groups (lecturers and students) were also investigated. What technique should be used toanalysethese data?

A

Three way mixed ANOVA

34
Q

An experiment was done to look at the positive arousing effects of imagery on different people. A sample of statistics lecturers was compared against a group of students. Both groups received presentations of positive images (e.g., cats and bunnies), neutral images (e.g., duvets and light bulbs), and negative images (e.g., corpses and vivisection photographs). Positive arousal was measured physiologically (high values indicate positive arousal) both before and after each batch of images. The order in which participants saw the batches of positive, neutral and negative images was randomized to avoid order effects. It was hypothesized that positive images would increase positive arousal, negative images would reduce positive arousal and that neutral images would have no effect.
What is the IV?

What is the DV?

What is the design?

A

IV1- Stats lecturers versus students (BS).
IV2 - Positive, neutral and negative images (WS)
IV3 - arousal measurements(WS)
DV - positive arousal
Design – mixed model

35
Q

An experiment was done to look at the positive arousing effects of imagery on different people. A sample of statistics lecturers was compared against a group of students. Both groups received presentations of positive images (e.g., cats and bunnies), neutral images (e.g., duvets and light bulbs), and negative images (e.g., corpses and vivisection photographs). Positive arousal was measured physiologically (high values indicate positive arousal) both before and after each batch of images. The order in which participants saw the batches of positive, neutral and negative images was randomized to avoid order effects. It was hypothesized that positive images would increase positive arousal, negative images would reduce positive arousal and that neutral images would have no effect. What technique should be used to analyse these data?

A

Three-way mixed ANOVA, why?
We could run a 2 (Time: before and after)×2 (Group: students and lecturers)×3 (Image: positive, negative and neutral) mixed ANOVA with between subjects on the Group variable

36
Q

An experiment was conducted to see how people with eating disorders differ in their need to exert control in different domains. Participants were classified as not having an eating disorder (control), as having anorexia nervosa (anorexic), or as having bulimia nervosa (bulimic). Each participant underwent an experiment that indicated how much they felt the need to exert control in three domains: eating, friendships and the physical world (this final category was a control domain in which the need to have control over things like gravity or the weather was assessed). So all participants gave three responses in the form of a mean reaction time; a low reaction time meant that the person did feel the need to exert control in that domain. The variables have been labelled as group (control, anorexic, or bulimic) and domain (food, friends, or physical laws). Of the following options, which analysis should be conducted?

A

Two-way mixed ANOVA

37
Q

Partial eta squared is made up of what?

A

SS(effect)/SS(effect + SS(error))

38
Q

WHICH OF THE DESIGNS WOULD BE BEST SUITED TO ANCOVA?
A. Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group. Their levels of stress were measured and compared after 3 months of weekly therapy sessions.
B. Participants were allocated to one of two stress management therapy groups, or a waiting list control group based on their baseline levels of stress. The researcher was interested in investigating whether stress after the therapy was successful partialling out their baseline anxiety.
C. Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group. The researcher was interested in the relationship between the therapist’s ratings of improvement and stress levels over a 3-month treatment period.
D. Participants were randomly allocated to one of two stress management therapy groups, or a waiting list control group. Their baseline levels of stress were measured before treatment, and again after 3 months of weekly therapy sessions.

A

D

39
Q

Identify the IV, DV, and covariates
A researcher was interested in measuring the effect of 3 different anxiety medications on patients diagnosed with anxiety disorder. They measured anxiety levels before and after treatment of 3 different treatment groups plus a control group. The researchers also collected data on depression levels.

A

IV: anxiety medication
Covariate: anxiety before treatment, depression
DV: anxiety after treatment

40
Q

Identify the IV’s and DV
Researchers wanted to see how much people of different education levels are interested in politics. They also believed that there might be an effect of gender. They measured political interest with a questionnaire in males and females that had either school, college or university education.

A

IVs: gender & education level
DV: political interest
🡪 Two-way independent ANOVA

41
Q

What test should be used for this?
An experiment was done to look at whether there is an effect of both gender and the number of hours spent practising a musical instrument on the level of musical ability.
A sample of 30 participants (15 men and 15 women) who had never learnt to play a musical instrument before were recruited. Participants were randomly allocated to one of three groups that varied in the number of hours they would spend practising every day for 1 year (0 hours, 1 hours, 2 hours). Men and women were divided equally across groups.
All participants had a one-hour lesson each week over the course of the year, after which their level of musical skill was measured on a 10-point scale ranging from 0 (you can’t play for toffee) to 10 (‘Are you Mozart reincarnated?’).

A

Two-way independent ANOVA

42
Q

Describe a covariate

A

A variable that shares some of the variance of another variable in which the researcher is interested.

43
Q

TWO-WAY ANOVA IS BASICALLY THE SAME AS ONE-WAY ANOVA, EXCEPT THAT

A

The model sum of squares is partitioned into three parts

44
Q

IF WE WERE TO RUN A FOUR-WAY BETWEEN-GROUPS ANOVA, HOW MANY SOURCES OF VARIANCE WOULD THERE BE?

A

16

45
Q

What does Cohen’s D tell us?

A

The size of our effect by the x amount of SD’s in t-tests
Rule of thumb:
small = 0.2
Medium = 0.5
Large = 0.8

46
Q

How important is Cohen’s D?

A

the importance of an effect is ALWAYS dependent to your research question

47
Q

If you use a paired samples t-test
A. Other things being equal, you do not need as many participants as you would for an independent samples design.
B. The same participants take part in both experimental conditions.
C. There ought to be less unsystematic variance compared to the independent t-test.
D. All of these are correct.

A

D

48
Q

An experiment was done to look at whether different relaxation techniques could predict sleep quality better than nothing. A sample of 400 participants were randomly allocated to one of four groups: massage, hot bath, reading or nothing. For one month each participant received one of these relaxation techniques for 30 minutes before going to bed each night. A special device was attached to the participant’s wrist that recorded their quality of sleep, providing them with a score out of 100. The outcome was the average quality of sleep score over the course of the month.Which test could we use to analyse these data?

A

Regression or ANOVA

49
Q

Imagine you compare the effectiveness of four different types of stimulant to keep you awake while revising statistics using a one-way ANOVA. The null hypothesis would be that all four treatments have the same effect on the mean time kept awake. How would you interpret the alternative hypothesis?

A

At least two of the stimulants will have different effects on the mean time spent awake

50
Q

What is an omnibus test?

A

Any statistical test that tests for the significance of several parameters in a model at once

51
Q

Subsequent to obtaining a significant result from an exploratory one-way independent ANOVA, a researcher decided to conduct three post hoct-tests to investigate where the differences between groups lie.Which of the following statements is correct?
A. The researcher should accept as statistically significant tests with a probability value of less than 0.016 to avoid making a Type I error
B. The researcher should have conducted orthogonal contrasts instead oft-tests to avoid making a Type I error
C. This is the wrong method to use. The researcher did not make any predictions about which groups will differ before running the experiment, therefore contrasts andpost hoctests cannot be used
D. None of these options are correct

A

A

52
Q

Which of the following statements about the t-statistic in regression is not true?

A. The t-statistic tests whether the regression coefficient, b, is equal to 0.
The t-statistic can be used to see whether a predictor variable makes a statistically significant contribution to the regression model.
The t-statistic provides some idea of how well a predictor predicts the outcome variable.
The t-statistic is equal to the regression coefficient divided by its standard deviation.

A

D

53
Q

What is partial correlation?

A

The amount of variance the variable explains relative to the amount of variance in the outcome that left to explain after the contribution of other predictors have been removed from both the predictor and outcome

54
Q

A semi-partial correlation tells us what?

A

It quantifies the relationship between two variables while accounting for the effects of a third variable on only one of the variables in the original correlation.

55
Q

Which of the following statements about Pearson’s correlation coefficient isnottrue?
A. It can only be used with continuous variables
B. It can be used as an effect size measure
C. It varies between –1 and +1
D. A correlation coefficient of zero indicates there is no relationship between the variables

A

A

56
Q

True or False: Pearson’s correlation coefficient can only be used with continuous variables

A

False
Biserial correlation
Point-biserial correlation

57
Q

What is biserial correlation?

A

When one variable is dichotomous, but there is an underlying continuum (i.e pass/fail on an exam)

58
Q

What is point-biserial correlation?

A

When one variable is dichotomous and it is a true dichotomy (i.e pregnant/not pregnant)

59
Q

The coefficient of determination is what?

A

A measure of the amount of variability in one variable that is shared by the other variable (r squared value)

60
Q

What is a z-score?

A

A measure of variability, the number of SD’s from the pop mean or a particular data point
A standardised measure, so they ignore measurement units

61
Q

What does a 95% confidence interval of the mean, mean?

A

95 out of 100 confidence intervals will contain the population mean

62
Q

Skewness should fall between what?

A

-1 and 1
if its <-1 its negative if its > 1 its positive

63
Q

Kurtosis should fall between what?

A

-2 and 2
if its <-2 its platykurtic (will be tall and thin) if its > 2 its leptokurtic (wide and flat)

64
Q

What is a confounding variable?

A

Also known as a tertrium quid
The third variable that is not accounted for

65
Q

The purpose of a control condition is to:

A

Allow inferences about cause

66
Q

Which of the following is NOT an assumption of the General Linear Model?
Dependence
Additivity
Linearity
Normally distributed residuals

A

Dependence

67
Q

Stepwise Regression

A

If the goal is accurate statistical prediction from a large number of predictor variables – computer driven

68
Q

Hierarchal Regression

A

To test predictor variables in a specific order based on hypotheses derived from theory

69
Q

Standard Regression

A

To assess impact of all predictor variables simultaneously

Stats - Research and Design (5 decks)

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