# Repeated-Measures Study – T Statistic Exam

## Repeated-Measures Study, Rejecting The Null Hypothesis

The key terms in these Statistic chapters include Repeated-Measures Study, Repeated Measures T Test, Sample Mean, Rejecting The Null, Repeated-Measures T Statistic, Rejecting The Null Hypothesis, Independent-Measures Study, Sample, Variance, Research Design, Correlation, Research Study.

A repeated-measures study and an independent-measures study both produce a t statistic with df = 20. The repeated-measures study used more subjects than the independent-measures study.

False

For a repeated-measures study, if the null hypothesis is true, then what value should be obtained for the sample mean.

MD near 0

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

A large number of scores and a small variance

For a repeated-measures study, a small variance for the difference scores indicates that the treatment has little or no effect.

False

For a repeated-measures study, if the null hypothesis is true, then what value should be obtained for the sample mean.

##### MD near 0

For the following data from a repeated-measures study, the sample mean difference is MD = 1Participant X1 X2
A 1 5
B 4 6
C 5 2

True

A repeated-measures study and an independent-measures study both produce a t statistic with df = 20. The repeated-measures study used more subjects than the independent-measures study.

False

In a repeated measures study, the null hypothesis says that the mean for the sample of difference scores is equal to zero.

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.

False

The estimated standard error in the denominator of the repeated-measures t statistic measures the average mean difference that is expected for a sample selected from a population with a zero mean difference.

True

For which of the following situations would a repeated-measures research design be appropriate?

Comparing pain tolerance with and without acupuncture needles

Which of the following is the correct null hypothesis for a repeated-measures t test?

#### mD = 0

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

A large number of scores and a small variance

Although a repeated-measures study measures two scores for each participant, the sample mean and variance are computed using only one score for each participant.

True

A researcher reports df = 18 for a repeated-measures t statistic. This research study used a total of n = 19 participants.

True

For a repeated-measures study, as the variance of the difference scores increases, the likelihood of finding a significant difference also increases.

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 = 18.

False

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

An increase in the standard error and a decrease in the value of t

A research report describing the results from a repeated-measures study states that the data show no significant difference between the two treatments, t(10) = 1.65, p > .05. Based on this report, how many individuals participated in the research study?

#### 11

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

19

A repeated-measures study comparing two treatments with a sample of n = 4 participants produces MD = 3 with SS = 48 for the set of difference scores. What is the repeated-measures t statistic for these data?

3/2 = 1.50

A set of n = 16 difference scores has a mean of MD = 4 and a variance of s2 = 36. Cohen’s d for this sample is d = 4/6.

True

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?

##### MD = 2

Which of the following describes the effect of increasing sample size?

There is little or no effect on measures of effect size, but the likelihood of rejecting the null hypothesis increases.

Delores must grade a driver’s test completed by a group of training students. She knows that driver’s test scores are normally distributed with µ = 50 and σ = 6. Students are required to score in the top 75% of students on the test in order to pass the test and continue on with the training course. Which score do students need to obtain at a minimum in order to pass the test and continue with the course?

##### X = 46

A highly selective university requires that applying students complete an entrance exam with µ = 60 and σ = 16. Applying students must avoid scoring in the bottom 89.5% of scores on the exam in order to be accepted into the university. Applicants must score more than _____ in order to be accepted to the university.

X = 80

A set of X and Y scores has M X = 4, SS X = 10, M Y = 5, SS Y = 40, and SP = 20. Which is the regression equation for predicting Y from X?

Ŷ = 2X – 3

A set of n = 15 pairs of scores ( X and Y values) produces a correlation of r = 0.40. If each of the X values are multiplied by 2 and the correlation is computed for the new scores, which value will be obtained for the new correlation?

#### r = 0.40

Which correlation should be used to measure the relationship between gender and grade point average for a group of college students?

point-biserial correlation (used when one variable is dichotomous)

A researcher assesses self-esteem among college students at the beginning of the semester using a self-report questionnaire, as well as three months later at the end of the semester among the same sample of college students using the exact same self-report measure of self-esteem. The researcher determines that there is a significant positive relationship between self-esteem measured at the beginning and end of the college semester for the students sampled. This demonstrates how correlations can be used to demonstrate _____.

Reliability

As the sample size gets larger, the size of the correlation needed for significance _____

Gets smaller

For the following data from a repeated-measures study, the sample mean difference is MD = 1Participant X1 X2
A 1 5
B 4 6
C 5 2

True

For a repeated-measures study, a small variance for the difference scores indicates that the treatment has little or no effect.

False

In a repeated measures study, the null hypothesis says that the mean for the sample of difference scores is equal to zero.

False

For which of the following situations would a repeated-measures research design be appropriate?

Comparing pain tolerance with and without acupuncture needles

Which of the following is the correct null hypothesis for a repeated-measures t test?

#### mD = 0

A researcher reports df = 18 for a repeated-measures t statistic. This research study used a total of n = 19 participants.

True

For a repeated-measures study, as the variance of the difference scores increases, the likelihood of finding a significant difference also increases.

False

A research report describing the results from a repeated-measures study states that the data show no significant difference between the two treatments, t(10) = 1.65, p > .05. Based on this report, how many individuals participated in the research study?

#### 11

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

19

A repeated-measures study comparing two treatments with a sample of n = 4 participants produces MD = 3 with SS = 48 for the set of difference scores. What is the repeated-measures t statistic for these data?

3/2 = 1.50

A set of n = 16 difference scores has a mean of MD = 4 and a variance of s2 = 36. Cohen’s d for this sample is d = 4/6.

True

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