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For the independent-measures t statistic, what is the effect of increasing the difference between sample means?
Increase the likelihood of rejecting H0 and increase measures of effect size.
Increase the likelihood of rejecting H0 and decrease measures of effect size.
Decrease the likelihood of rejecting H0 and increase measures of effect size.
Decrease the likelihood of rejecting H0 and decrease measures of effect size.

 

If one sample has n = 5 scores with SS = 40 and a second sample has n = 5 scores with SS = 20, then the pooled variance will be 60/10 = 6.
True
False

 

For the independent-measures t statistic, what is the effect of increasing the sample variances?
Increase the likelihood of rejecting H0 and increase measures of effect size.
Increase the likelihood of rejecting H0 and decrease measures of effect size.
Decrease the likelihood of rejecting H0 and increase measures of effect size.
Decrease the likelihood of rejecting H0 and decrease measures of effect size.

 

The null hypothesis for the independent-measures t test states that there is no difference between the two sample means.
True
False

The results of an independent-measures research study are reported as “t(20) = 2.12, p < .05, two tails.” For this study, what t values formed the boundaries for the critical region?
±2.093
±2.086
±2.080
±2.074

±2.086

Two samples, each with n = 6 subjects, produce a pooled variance of 20. Based on this information, what is the estimated standard error for the sample mean difference?
20/6
20/12
The square root of (20/6 + 20/6)
The square root of (20/5 + 20/5)

 

For an independent-measures t statistic, what is the effect of increasing the number of scores in the samples?
Increase the likelihood of rejecting H0 and increase measures of effect size.
Increase the likelihood of rejecting H0 and decrease measures of effect size.
Increase the likelihood of rejecting H0 and have little or no effect on measures of effect size.
Decrease the likelihood of rejecting H0 and have little or no effect on measures of effect size.

 

Two samples, each with n = 9 scores, produce an independent-measures t statistic of t = 2.00. If the effect size is measured using r2, what is the value of r2?
4/16
4/20
2/16
2/18

 

For an independent-measures research study, what is measured by Cohen’s d or r2?
The risk of a Type I error
The risk of a Type II error
The size of the difference between the two treatments
Whether the difference between the two treatments is likely to have occurred by chance

 

When pooling variances, the resulting value will be closer to the variance for the sample with the smaller number of scores.
True
False

 

If two sample variances are not equal, the pooled variance will be closer to the larger of the two variances.
True
False

 

An independent-measures study has M1 = 49 and M2 = 45 with an estimated standard error of 4. For this study, Cohen’s d = 4/4 = 1.00.
True
False

 

If two samples each have s2 = 10, then the pooled variance will be equal to 20.
True
False

 

For a repeated-measures design, df = n1 + n2 – 2 for the t statistic.
True
False

 

A researcher would like to compare two treatment conditions with a set of 30 scores in each treatment. If a repeated-measures design is used, the study will require n = 60 participants.
True
False

 

A repeated-measures research study comparing two treatments with a set of 10 scores in each treatment will produce a t statistic with df = 19.
True
False

 

If the null hypothesis is true, what value is expected on average for the repeated-measures t statistic?
0
1
1.96
t 1.96

 

A repeated-measures study using a sample of n = 20 participants would produce a t statistic with df = ____.
9
19
20
39

 

Repeated-measures designs are particularly well-suited to research questions concerning the difference between two distinct populations (for example, males versus females).
True
False

 

For a research study comparing two treatment conditions, a repeated-measures design would require two scores for each participant but an independent-measures design would require only one score for each participant.
True
False

 

For which of the following situations would a repeated-measures research design be appropriate?
Comparing mathematical skills for girls versus boys at age 10
Comparing pain tolerance with and without acupuncture needles
Comparing self-esteem for students who participate in school athletics versus those who do not
Comparing verbal solving skills for science majors versus art majors at a college

 

What is the value of the estimated standard error for the following set of D-scores?
Scores: 2, 2, 10, 2
3
3.5
4
2

 

For the repeated-measures t statistic, df = ____.
n1 + n2 – 2
(n1 – 1) + (n2 – 1)
n – 1
n1 + n2 – 1

 

A repeated-measures test usually is more likely to detect a real treatment effect than an independent-measures test because the repeated-measures design typically has a smaller variance and a smaller estimated standard error.
True
False

 
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