Question 1

What value is estimated with a confidence interval using the repeated-measures t statistic?​

Accepted Answer

A confidence interval using the repeated-measures t statistic is used to estimate the mean for a population of difference scores, not just a sample. This approach is typically used in within-subjects designs where the same subjects are measured under different conditions, and the interest is in estimating the mean difference in scores across these conditions for the entire population from which the sample was drawn.

Question 2

For a repeated-measures study comparing two treatment conditions,a researcher obtains Cohen's d = 0.50 for a sample of n = 4 scores with a variance of s² = 16.What is the value of the sample mean?

Accepted Answer

Cohen's d = (M1 - M2) / s0.50 = (M1 - M2) / 4M1 - M2 = 2M1 = M2 + 2

Question 3

Compared to an independent-measures design,a repeated-measured study is more likely to find a significant effect because it reduces the contribution of variance due to ____.​

Accepted Answer

In a repeated-measures design, each participant is observed multiple times, which reduces the influence of individual differences and increases the power to detect the effect of the treatment. In an independent-measures design, individual differences can contribute more to the variance and decrease the chances of finding a significant effect. Therefore, the correct answer is individual differences (D). The other options do not make sense in this context.

Question 4

A researcher obtains t(20)= 2.00 and M_D = 9 for a repeated-measures study.If the researcher measures effect size using the percentage of variance accounted for,what value will be obtained for r²?

Accepted Answer

The answer of A researcher obtains t(20)= 2.00 and M_D...

Question 5

A sample of n = 9 college students is used to evaluate the effectiveness of a new Study Skills Workshop.Each student's grade point average (GPA)is recorded for the semester before the workshop and for the semester after the workshop.The average GPA improved by M_D = 0.60 points with s² = 0.09.The researcher would like to use the sample to estimate how much effect the workshop would have for the entire college population.What is the 80% confidence interval for these data?

Accepted Answer

The answer of A sample of n = 9 college...

Question 6

Which possible outcome is of serious concern with a repeated-measures study?​

Accepted Answer

In a repeated-measures study, order effects are a serious concern. These are the effects that result from the order in which the conditions are presented to the participants. For example, if a participant completes the same task multiple times, they may get better at it simply due to practice or fatigue, which can lead to misleading results. Researchers need to control for these effects by counterbalancing the order of conditions or using a within-subjects design.

Question 7

A repeated-measures design has the maximum advantage over an independent-measures design when ____.​

Accepted Answer

A repeated-measures design is most advantageous when there are few subjects available and individual differences among subjects are large. This design allows each participant to serve as their own control, thus controlling for individual differences and requiring fewer participants.

Question 8

A research report describing the results from a repeated-measures study states: The data show no significant difference between the two treatments,t(10)= 1.65,p > .05.Based on this report,you can conclude that a total of ____ individuals participated in the research study.​

Accepted Answer

In a repeated-measures study, the degrees of freedom (df) for a t-test are calculated as the number of subjects minus one (N-1). The report mentions t(10), indicating the degrees of freedom are 10, which means there were 11 participants (since 10 + 1 = 11).

Question 9

If the sample size is held constant,which of the following will produce the widest 90% confidence interval for the population mean difference for a repeated-measures study?​

Accepted Answer

The confidence interval for the difference in means is calculated as (point estimate) ± t(df, α/2) * (standard error of the difference), where - the point estimate is the sample mean difference - t(df, α/2) is the critical value from the t-distribution, with df degrees of freedom and α/2 significance level (for a 90% confidence interval, α = 0.1 and α/2 = 0.05) - the standard error of the difference is calculated as s / sqrt(n), where s is the sample standard deviation of the difference scores, and n is the sample size To produce the widest confidence interval for the population mean difference, we want the standard error of the difference to be as large as possible, while keeping the sample size constant. Therefore, we want the sample standard deviation of the difference scores to be as large as possible, given the same sample size. Choice D has the largest s² value (20), so it will produce the widest confidence interval.

Question 10

In a repeated-measures experiment,each individual participates in one treatment condition and then moves on to a second treatment condition.One of the major concerns in this type of study is that participation in the first treatment may influence the participant's score in the second treatment.This problem is referred to as ____.​

Accepted Answer

Order effects refer to the possibility that the order in which treatments are given in a repeated-measures experiment may influence participants' scores in the second treatment. This can happen because participants may learn or become fatigued, for example, during the first treatment, which could affect their performance in the second treatment. Individual differences, homogeneity of variance, and bi-treatment effects are not specifically related to this type of problem.

Question 11

In general,what is the effect of an increase in the variance for the sample of difference scores?​

Accepted Answer

An increase in the variance of the sample of difference scores leads to an increase in the standard error, which means the scores are more spread out and less reliable. This, in turn, leads to a decrease in the value of t, as the sample means are less likely to represent the true population mean. Therefore, the best choice is B - an increase in the standard error and a decrease in the value of t.

Question 12

In general,what characteristics of the difference scores are most likely to produce a significant t statistic for the repeated-measures hypothesis test?​

Accepted Answer

A large number of scores increases the power of the test, but having a small variance in the difference scores indicates that the condition is having a consistent effect and reduces the amount of noise in the data, making it easier to detect a significant difference.

Question 13

A researcher is using a repeated-measures study to evaluate the difference between two treatments.If the difference between the treatments is consistent from one participant to another,then the data should produce a ____.​

Accepted Answer

If the difference between the treatments is consistent from one participant to another, then the difference scores should show little variation (small variance), and the standard error should be small as well. This indicates that the treatment effect is reliable and consistent across the sample.

Question 14

A researcher reports t(12)= 2.86,p < .05 for a repeated-measures research study.How many individuals participated in the study?​

Accepted Answer

The "n" value for a t-test with 12 degrees of freedom would be 13, as the sample size for a repeated-measures study is equal to the number of participants in the study. Also, the p-value being less than .05 indicates that the results are statistically significant at the 5% level.

Question 15

In general,if the variance of the difference scores increases,then what will happen to the value of the t statistic?​

Accepted Answer

The t statistic is inversely related to the variance of the difference scores. As the variance increases, the denominator in the t formula (which includes the standard error, itself a function of variance) increases, leading to a smaller t value, hence moving it toward 0 at the center of the distribution.

Question 16

A researcher uses a repeated-measures design to compare individuals' performance before treatment with their performance after treatment.If all of the participants show improved performance of 8 or 9 points after treatment,then the researcher should find ____.​

Accepted Answer

The variance of the difference scores is near zero because all participants show a consistent improvement (either 8 or 9 points), indicating very little variability in how much each participant improved.

Question 17

What is indicated by a large variance for a sample of difference scores?​

Accepted Answer

A large variance in difference scores suggests that the treatment effect is not consistent across the sample, leading to a lower likelihood of identifying a significant difference due to the increased variability.

Question 18

A research report describing the results from a repeated-measures t test states,"t(22)= 1.71,p > .05." From this report you can conclude that the outcome of the hypothesis test was to ____.​

Accepted Answer

The t-value of 1.71 is not significant at the .05 level (as indicated by p > .05), which means we fail to reject the null hypothesis. The sample size of 23 is not relevant to this conclusion as it is represented by the degrees of freedom (df) in the t-test equation, which is calculated as df = n - 1. In this case, df = 22, which is represented in the t(22) notation. Therefore, the correct answer is B: fail to reject the null hypothesis with a sample of n = 23 participants.

Question 19

A sample of difference scores has a mean of M_D = 5 with a variance of s² = 100.If effect size is measured using Cohen's d,what is the value of d?

Accepted Answer

Cohen's d is calculated as the mean difference divided by the standard deviation. Given a variance of 100, the standard deviation is the square root of 100, which is 10. Therefore, d = 5 / 10.

Question 20

Assuming that other factors are held constant,which approach would tend to increase the likelihood of rejecting the null hypothesis?​

Accepted Answer

Increasing the sample mean difference makes the difference between the two groups more pronounced, increasing the likelihood of rejecting the null hypothesis. Decreasing the sample size, increasing the sample variance, or decreasing the sample mean difference would all decrease the likelihood of rejecting the null hypothesis.

Quiz 11: The T Test for Two Related Samples

What value is estimated with a confidence interval using the repeated-measures t statistic?

For a repeated-measures study comparing two treatment conditions,a researcher obtains Cohen's d = 0.50 for a sample of n = 4 scores with a variance of s² = 16.What is the value of the sample mean?

Compared to an independent-measures design,a repeated-measured study is more likely to find a significant effect because it reduces the contribution of variance due to ____.

A researcher obtains t(20) = 2.00 and M_D = 9 for a repeated-measures study.If the researcher measures effect size using the percentage of variance accounted for,what value will be obtained for r²?

Which possible outcome is of serious concern with a repeated-measures study?

A repeated-measures design has the maximum advantage over an independent-measures design when ____.

A research report describing the results from a repeated-measures study states: The data show no significant difference between the two treatments,t(10) = 1.65,p > .05.Based on this report,you can conclude that a total of ____ individuals participated in the research study.

If the sample size is held constant,which of the following will produce the widest 90% confidence interval for the population mean difference for a repeated-measures study?

In general,what is the effect of an increase in the variance for the sample of difference scores?

In general,what characteristics of the difference scores are most likely to produce a significant t statistic for the repeated-measures hypothesis test?

A researcher is using a repeated-measures study to evaluate the difference between two treatments.If the difference between the treatments is consistent from one participant to another,then the data should produce a ____.

A researcher reports t(12) = 2.86,p < .05 for a repeated-measures research study.How many individuals participated in the study?

In general,if the variance of the difference scores increases,then what will happen to the value of the t statistic?

A researcher uses a repeated-measures design to compare individuals' performance before treatment with their performance after treatment.If all of the participants show improved performance of 8 or 9 points after treatment,then the researcher should find ____.

What is indicated by a large variance for a sample of difference scores?

A research report describing the results from a repeated-measures t test states,"t(22) = 1.71,p > .05." From this report you can conclude that the outcome of the hypothesis test was to ____.

A sample of difference scores has a mean of M_D = 5 with a variance of s² = 100.If effect size is measured using Cohen's d,what is the value of d?

Assuming that other factors are held constant,which approach would tend to increase the likelihood of rejecting the null hypothesis?

Quiz 11: The T Test for Two Related Samples

What value is estimated with a confidence interval using the repeated-measures t statistic?​

For a repeated-measures study comparing two treatment conditions,a researcher obtains Cohen's d = 0.50 for a sample of n = 4 scores with a variance of s2 = 16.What is the value of the sample mean?​

Compared to an independent-measures design,a repeated-measured study is more likely to find a significant effect because it reduces the contribution of variance due to ____.​

A researcher obtains t(20) = 2.00 and MD = 9 for a repeated-measures study.If the researcher measures effect size using the percentage of variance accounted for,what value will be obtained for r2?​

Which possible outcome is of serious concern with a repeated-measures study?​

A repeated-measures design has the maximum advantage over an independent-measures design when ____.​

A research report describing the results from a repeated-measures study states: The data show no significant difference between the two treatments,t(10) = 1.65,p > .05.Based on this report,you can conclude that a total of ____ individuals participated in the research study.​

If the sample size is held constant,which of the following will produce the widest 90% confidence interval for the population mean difference for a repeated-measures study?​

In general,what is the effect of an increase in the variance for the sample of difference scores?​

In general,what characteristics of the difference scores are most likely to produce a significant t statistic for the repeated-measures hypothesis test?​

A researcher is using a repeated-measures study to evaluate the difference between two treatments.If the difference between the treatments is consistent from one participant to another,then the data should produce a ____.​

A researcher reports t(12) = 2.86,p < .05 for a repeated-measures research study.How many individuals participated in the study?​

In general,if the variance of the difference scores increases,then what will happen to the value of the t statistic?​

A researcher uses a repeated-measures design to compare individuals' performance before treatment with their performance after treatment.If all of the participants show improved performance of 8 or 9 points after treatment,then the researcher should find ____.​

What is indicated by a large variance for a sample of difference scores?​

A research report describing the results from a repeated-measures t test states,"t(22) = 1.71,p > .05." From this report you can conclude that the outcome of the hypothesis test was to ____.​

A sample of difference scores has a mean of MD = 5 with a variance of s2 = 100.If effect size is measured using Cohen's d,what is the value of d?​

Assuming that other factors are held constant,which approach would tend to increase the likelihood of rejecting the null hypothesis?​

What value is estimated with a confidence interval using the repeated-measures t statistic?

For a repeated-measures study comparing two treatment conditions,a researcher obtains Cohen's d = 0.50 for a sample of n = 4 scores with a variance of s² = 16.What is the value of the sample mean?

Compared to an independent-measures design,a repeated-measured study is more likely to find a significant effect because it reduces the contribution of variance due to ____.

A researcher obtains t(20) = 2.00 and M_D = 9 for a repeated-measures study.If the researcher measures effect size using the percentage of variance accounted for,what value will be obtained for r²?

Which possible outcome is of serious concern with a repeated-measures study?

A repeated-measures design has the maximum advantage over an independent-measures design when ____.

A research report describing the results from a repeated-measures study states: The data show no significant difference between the two treatments,t(10) = 1.65,p > .05.Based on this report,you can conclude that a total of ____ individuals participated in the research study.

If the sample size is held constant,which of the following will produce the widest 90% confidence interval for the population mean difference for a repeated-measures study?

In general,what is the effect of an increase in the variance for the sample of difference scores?

In general,what characteristics of the difference scores are most likely to produce a significant t statistic for the repeated-measures hypothesis test?

A researcher is using a repeated-measures study to evaluate the difference between two treatments.If the difference between the treatments is consistent from one participant to another,then the data should produce a ____.

A researcher reports t(12) = 2.86,p < .05 for a repeated-measures research study.How many individuals participated in the study?

In general,if the variance of the difference scores increases,then what will happen to the value of the t statistic?

A researcher uses a repeated-measures design to compare individuals' performance before treatment with their performance after treatment.If all of the participants show improved performance of 8 or 9 points after treatment,then the researcher should find ____.

What is indicated by a large variance for a sample of difference scores?

A research report describing the results from a repeated-measures t test states,"t(22) = 1.71,p > .05." From this report you can conclude that the outcome of the hypothesis test was to ____.

A sample of difference scores has a mean of M_D = 5 with a variance of s² = 100.If effect size is measured using Cohen's d,what is the value of d?

Assuming that other factors are held constant,which approach would tend to increase the likelihood of rejecting the null hypothesis?