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Stats > Practice quizzes & Posttests FInal Exam > Flashcards

Practice quizzes & Posttests FInal Exam Flashcards

1
Q

Which inferential test should be used to compare two sample means to each other?
The two-sample t-test
The ratio of IQRs
The one-sample z-test
The one-sample t-test

A

The two-sample t-test

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2
Q

The most important difference between Cohen’s d and the t-test is that Cohen’s d…
can only be used for large samples (n > 30).
is not affected by sample size.
can only be used for two-group situation.
requires the population variance.

A

is not affected by sample size.

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3
Q

What is the formula for the degrees of freedom (df) for a two-sample t-test?
n - 1
n - 2
n - k - 1
√n

A

n - 2

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4
Q

If a researcher wants to compare the effects of an antidepressant to the effects of a placebo on levels of anxiety, then what is the independent variable (that is, the IV)?
Two-sample t-test
Antidepressant medication
Levels of anxiety
Medication: antidepressant vs. placebo

A

Medication: antidepressant vs. placebo

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5
Q

When the means of two groups are the same, then Cohen’s d…
will equal 0.
is equal to the combined sample sizes.
cannot be calculated.
will approach infinity.

A

will equal 0.

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6
Q

A two-sample t-test is an appropriate test when..
two samples are being compared on an interval or ratio level variable.
the data contain open-ended or undefined scores.
two samples are being compared on a nominal or ordinal level variable.
a sample mean being compared to a population mean

A

two samples are being compared on an interval or ratio level variable.

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7
Q

Imagine that a researcher conducts a one-tailed (i.e., directional) two-sample t-test with a critical value of -1.83 and gets an observed value (or test value) of t = +1.98. What is the proper conclusion in this case?
Retain the null hypothesis
Reject the null hypothesis
The researcher should use a two-tailed (i.e., nondirectional) test
Cannot be determined without additional information

A

Retain the null hypothesis

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8
Q

Cohen’s d indicates the number of…
standard errors between two means.
matching observations in two samples.
different observations in two samples.
standard deviations between two means.

A

standard deviations between two means.

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9
Q

If a researcher wants to compare the effects of an antidepressant to the effects of a placebo on levels of anxiety, then what is the dependent variable (that is, the DV)?
Levels of anxiety
Medication: antidepressant vs. placebo
Two-sample t-test
Antidepressant medication

A

Levels of anxiety

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10
Q

If a researcher gathers data from participants before and after they participate in an exercise training program and wants to know whether their performance scores improved, then he should use…
a one-tailed, one sample t-test.
a two-tailed, two-sample t-test.
a one-tailed, repeated measures t-test.
a two-tailed, repeated measures t-test.

A

a one-tailed, repeated measures t-test.

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11
Q

If a research conducts an inferential test (such as a t-test) and retains (i.e., fails to reject) the null hypothesis, then what is the probability of a Type I error?
0.00
.05
1.00 - p
1.00

A

0.00

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12
Q

One assumption of the two-sample t-test is that…
the data have a uniform distribution.
the two samples are independent of one another.
a two-tailed test will be used.
the two samples are as similar as possible.

A

the two samples are independent of one another.

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13
Q

Imagine that a researcher conducts a two-sample t-test with critical values of ±2.10 and gets an observed value (or test value) of t = 1.98. What is the proper conclusion in this case?
The research should use a z-test instead
Retain the null hypothesis
Reject the null hypothesis
Cannot be determined without additional information

A

Retain the null hypothesis

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14
Q

If a researcher wants to compare the effects of an antidepressant to the effects of a placebo on levels of anxiety, then what is the grouping variable?
Medication: antidepressant vs. placebo
Antidepressant medication
Levels of anxiety
Two-sample t-test

A

Medication: antidepressant vs. placebo

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15
Q

The comparison group in a repeated measures t-test is…
grouping variable.
each person’s own score at time 1.
the difference between each person’s time 1 and time 2 scores.
the mean for the general population.

A

each person’s own score at time 1.

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16
Q

Imagine that a researcher conducts a repeated measures t-test with critical values of ±2.78 and gets an observed value (or test value) of t = -3.30. What is the proper conclusion in this case?
Reject the null hypothesis
This is an impossible value of t for a repeated measures test
Retain the null hypothesis
Cannot be determined without additional information

A

Reject the null hypothesis

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17
Q

When the means of two samples are being compared and Cohen’s d = 0, then…
the means are identical.
n must be 0 also.
the distributions must have the same standard deviation as well as the same mean.
there is no variation in the data.

A

the means are identical.

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18
Q

If a research conducts an inferential test (such as a t-test) and rejects the null hypothesis, then what is the probability of a Type II error?
0.00
1.00 - p
1.00
.05

A

0.00

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19
Q

If n = ∞, then what is the critical value of t for alpha = .05?
±3.30
±1.96
0.00
Cannot be determined without additional information

A

±1.96

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20
Q

If a researcher conducts a t-test with an alpha of .01 and gets a p-value of .25, then the researcher should…
retain (i.e, fail to reject) the null hypothesis.
transform the data.
switch to the standard alpha of .05.
reject the null hypothesis.

A

retain (i.e, fail to reject) the null hypothesis.

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21
Q

If you want to compare the means of two different groups to each other then you should use…
a two-sample t-test.
the ratio of standard errors.
a one-sample z-test.
a one-sample t-test.

A

a two-sample t-test.

22
Q

What is the formula for the degrees of freedom (df) for a two-sample t-test?
n - 1
n - k -1
n - 2

A

n-2

23
Q

As the means of two groups become more similar, Cohen’s d will…
approach 0.
become positively skewed.
approach infinity.
become impossible to calculate.

A

approach 0.

24
Q

If you conduct a one-tailed (i.e., directional) two-sample t-test with a critical value of +2.20 and gets an observed value of t = -3.53, then what should you do?
Cannot be determined without additional information
Use a two-tailed (i.e., nondirectional) test instead
Retain the null hypothesis
Reject the null hypothesis

A

Retain the null hypothesis

25
Q

If you conducted an experiment to compare the effects of two different online ad campaigns on the number of clickthroughs (i.e., how often people clicked on each ad), then what is the dependent variable (DV)?
Online samples
Ad campaign
The number of clickthroughs
Two-sample t-test

A

The number of clickthroughs

26
Q

If you conduct an inferential test and retain the null hypothesis, then what is the chance of a Type I error?
0.00
.05
1.00
alpha

A

0.00

27
Q

Imagine that you conduct a two-sample t-test with critical values of ±2.30 and gets an observed value (or test value) of t = -2.09. What should you do?
Retain the null hypothesis
Cannot be determined without additional information
Use a z-test instead
Reject the null hypothesis

A

Retain the null hypothesis

28
Q

The comparison group in a repeated-measures t-test is…
the grouping variable.
each person’s own score at time 1.
the mean for the general population.
the difference between each person’s time 1 and time 2 scores.

A

each person’s own score at time 1.

29
Q

If n = ∞, then what is the critical value of t for alpha = .05?
±1.96
0.00
t cannot be used when n = ∞
∞

A

±1.96

30
Q

When the means of two samples are being compared and Cohen’s d = 1.10, then…
you should reject the null hypothesis.
the means are 1.1 standard deviations apart.
an error was made because d can never be greater than ±1.00.
t will be statistically significant.

A

the means are 1.1 standard deviations apart.

31
Q

The analysis of variance (or ANOVA) is the preferred inferential test when you need to…
compare the means of three or more groups.
standardize all of the scores.
compare the scores of a group of participants before and after a manipulation
find the association between two quantitative variables.

A

compare the means of three or more groups.

32
Q

If an ANOVA is statistically significant, what does that mean?
The variance of the group means is less than 0.
The group means are all different from one another.
The variance of the group means is equal to 0.
The variance of the group means is greater than 0.

A

The variance of the group means is greater than 0.

33
Q

What is the symbol for the test statistic in ANOVA?
F
p
z
t

A

F

34
Q

What is the most common measure of effect size for ANOVA?
eta-squared
Cohen’s d
z
The standard error

A

eta-squared

35
Q

In order to calculate eta-squared, you first need to know…
the sum of squares (SS).
whether the F test is statistically significant.
Cohen’s d.
the shape of the distribution.

A

the sum of squares (SS).

36
Q

The analysis of variance is useful if you want to…
compare the number of men and women in different political parties.
compare the mean incomes of people in several different jobs.
test the change in scores for a group of people before and after an intervention.
compare the mean income of men and women.

A

compare the mean incomes of people in several different jobs

37
Q

The version of ANOVA that is used to compare, for example, the well-being of people from the three largest countries in North America is called the…
three-way ANOVA.
one-way ANOVA.
population ANOVA.
factorial ANOVA.

A

one-way ANOVA.

38
Q

What is the null hypothesis for ANOVA?

All group distributions are identical
The differences between groups are smaller than the differences within groups
All group means are equal

A

All group means are equal

39
Q

Imagine a study that compared men and women (the gender factor) and who were social liberal or conservative (the social attitudes factor) on levels of empathy. If there were significant differences between men and women, regardless of social attitudes, then the gender factor would be called…
a significant main effect.
a spurious effect.
a significant interaction effect.
a significant manipulation effect.

A

a significant main effect.

40
Q

In order to conduct an ANOVA, the dependent variable (DV) must be…
a continuous variable.
an interval or ratio level variable.
a nominal variable.
a ratio level variable only.

A

an interval or ratio level variable.

41
Q

Why is it better to use a one-way ANOVA than multiple t-tests to compare the means of several groups?
ANOVA handles missing data better
ANOVA handles large sample sizes better
Multiple t-tests inflate the Type I error rate
Multiple t-tests inflate the Type II error rate

A

Multiple t-tests inflate the Type I error rate

41
Q

Which of the following numbers is a possible value for eta-squared?
.16
-3.30
-0.39
1.96

A

.16

42
Q

If an ANOVA is conducted and eta-squared is .10, then…
10% of the variance in the DV can be predicted by the IV(s).
10% of the scores on the DV can be correctly predicted.
10% of the scores have missing values.
the null hypothesis should be retained.

A

10% of the variance in the DV can be predicted by the IV(s).

43
Q

Imagine a study that compared men and women (the gender factor) and who were social liberal or conservative (the social attitudes factor) on levels of empathy. If there were significant differences between people with liberal and conservative social attitudes, regardless of gender, then the attitude factor would be called…
a significant manipulation effect.
a significant interaction effect.
a spurious effect.
a significant main effect.

A

a significant main effect.

44
Q

What is the purpose of a post-hoc test?
To determine whether there are any interaction effects.
To calculate the effect size, eta-squared.
To determine whether the sample size was sufficient.
To find out which groups (or combinations of groups) are different from each other

A

To find out which groups (or combinations of groups) are different from each other

45
Q

When calculating probability values for ANOVA, the correct distribution is the…
t distribution.
F distribution.
standard normal distribution.
p distribution.

A

F distribution.

46
Q

When it is appropriate to conduct post-hoc tests?
Whenever an ANOVA is not statistically significant
Whenever an ANOVA is statistically significant
Whenever eta-squared is greater than 1
Whenever the data are normally distributed

A

Whenever an ANOVA is statistically significant

47
Q

Imagine a study that compared men and women (the gender factor) and who were social liberal or conservative (the social attitudes factor) on levels of empathy. If the the difference between men and women was different for people who were social liberal or conservative, then this result would be called…
a spurious effect.
a significant main effect.
a significant manipulation effect.
a significant interaction effect.

A

a significant interaction effect.

48
Q

What effects are shown in this chart? (pic #1)

Factor A: significant main effect; Factor B: significant main effect; AxB: no interaction
Factor A: significant main effect; Factor B: significant main effect; AxB: significant interaction
Factor A: no main effect; Factor B: significant main effect; AxB: no interaction
Factor A: significant main effect; Factor B: no main effect; AxB: no interaction

A

Factor A: no main effect; Factor B: significant main effect; AxB: no interaction

49
Q

What effects are shown in this chart? (pic#2)

Factor A: no main effect; Factor B: no main effect; AxB: no interaction
Factor A: significant main effect; Factor B: significant main effect; AxB: significant interaction
Factor A: no main effect; Factor B: no main effect; AxB: significant interaction
Factor A: significant main effect; Factor B: significant main effect; AxB: no interaction

A

Factor A: no main effect; Factor B: no main effect; AxB: significant interaction

50
Q

ON chapter 10 posttest

A

Stats (7 decks)

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