Question 1

A sample has three individuals, with scores of 2, 3, and 4. What is the estimated population variance?

Accepted Answer

A) 1 
B) 1.33 
C) 2 
D) 3.67 
A) 1 
B) 1.33 
C) 2 
D) 3.67

Question 2

For the following question(s): A school counselor claims that he has developed a technique to reduce prestudying procrastination in students. He has students time their procrastination for a week and uses this as a pretest (before)indicator of procrastination. Students then attend a workshop in which they are instructed to do a specific warming-up exercise for studying by focusing on a pleasant activity. For the next week, students again time their procrastination. The counselor then uses the time from this week as the posttest (after)measure.
-Suppose the counselor wants to examine whether there is a change of any kind (either an increase or decrease)in procrastination after attending his workshop. What would be the appropriate description of "Population 2" (the population to which the population his sample represents is being compared)?

Accepted Answer

A) People whose posttest scores will be lower than their pretest scores 
B) People whose change scores will be greater than 0 
C) People whose change scores will be 0 
D) People whose change scores will be less than their pretest scores 
A) People whose posttest scores will be lower than their pretest scores 
B) People whose change scores will be greater than 0 
C) People whose change scores will be 0 
D) People whose change scores will be less than their pretest scores

Question 3

With a t test for dependent means, Population 2 will ordinarily have a mean of:

Accepted Answer

A) -1 
B) 0 
C) +1 
D) it varies from sample to sample 
A) -1 
B) 0 
C) +1 
D) it varies from sample to sample

Question 4

In a study with 10 degrees of freedom, what would be your cutoff score for a t distribution using a one-tailed test at the .05 level of significance?

Accepted Answer

A) 1.372 
B) 1.813 
C) 2.764 
D) 2.228 
A) 1.372 
B) 1.813 
C) 2.764 
D) 2.228

Question 5

It takes a slightly __________ sample mean to get a significant result when using a t distribution than when using a normal curve.

Accepted Answer

A) more negative 
B) less extreme 
C) more extreme 
D) more exact 
A) more negative 
B) less extreme 
C) more extreme 
D) more exact

Question 6

Which of the following is TRUE?

Accepted Answer

A) An example of an unbiased estimate is the variance of a sample; a typical biased estimate is the researcher's initial expectation prior to sampling. 
B) There is only one biased estimate (i.e., the researcher's expected findings); there are several unbiased estimates. 
C) A biased estimate is preferred to an unbiased estimate when the population is not normally distributed. 
D) A sample's variance is a biased estimate of the population's variance, but a slight change in the variance formula gives an unbiased estimate. 
A) An example of an unbiased estimate is the variance of a sample; a typical biased estimate is the researcher's initial expectation prior to sampling. 
B) There is only one biased estimate (i.e., the researcher's expected findings); there are several unbiased estimates. 
C) A biased estimate is preferred to an unbiased estimate when the population is not normally distributed. 
D) A sample's variance is a biased estimate of the population's variance, but a slight change in the variance formula gives an unbiased estimate.

Question 7

If Professor Juarez had 30 students in her class, and she wanted to test her hypothesis using the 5% level of significance, what cutoff t score would she use? (You should be able to figure this out without a table because only one answer is in the correct region.)

Accepted Answer

A) 304.11 
B) 1.699 
C) -.113 
D) -2.500 
A) 304.11 
B) 1.699 
C) -.113 
D) -2.500

Question 8

The _________ is assumed to be 0 when doing a t test using difference scores.

Accepted Answer

mean of Population 2, mean of

Question 9

The t test for dependent means is also called a:

Accepted Answer

paired-sample t test, t test f

Question 10

What is often a limitation of research using a repeated-measure design?

Accepted Answer

A) low power 
B) lack of control group 
C) low standard deviation of difference scores 
D) all of the above 
A) low power 
B) lack of control group 
C) low standard deviation of difference scores 
D) all of the above

Question 11

If 15 research participants take a pretest and a posttest with a mean change score of 1.5, and if the standard deviation of the comparison distribution is .5, what is the t score?

Accepted Answer

A) 1.5/(15 - 1)= .11 
B) 1.5/15 = .10 
C) 1.5/.5 = 3.00 
D) 15/1.5 = 10 
A) 1.5/(15 - 1)= .11 
B) 1.5/15 = .10 
C) 1.5/.5 = 3.00 
D) 15/1.5 = 10

Question 12

Student's t was created by __________.

Accepted Answer

William S.

Question 13

In a t test for dependent means, the mean change score is 12 and the standard deviation of the distribution of means is 6. What is the t score?

Accepted Answer

The answer of In a t test for dependent means,...

Question 14

Suppose the standard deviation she figures (the square root of the unbiased estimate of the population variance)is .85. What is the effect size?

Accepted Answer

A) 5/.85 = 5.88 
B)  .85/5 = .17 
C) (5 - 4.4)/.85 = .71 
D)  .85/(5 -4.4)= 1.42 
A) 5/.85 = 5.88 
B)  .85/5 = .17 
C) (5 - 4.4)/.85 = .71 
D)  .85/(5 -4.4)= 1.42

Question 15

The estimated effect size for a study using a t test for dependent means is the mean of the difference scores divided by the:

Accepted Answer

A) difference scores 
B) estimated variance of the sample of difference scores 
C) estimated standard deviation of the population of difference scores 
D) estimated mean of the population of difference scores 
A) difference scores 
B) estimated variance of the sample of difference scores 
C) estimated standard deviation of the population of difference scores 
D) estimated mean of the population of difference scores

Question 16

Which of the following is the most likely way for results of a t test for dependent means to be presented in a research article for a study with 25 participants?

Accepted Answer

A) t test(25)< significant 
B) t test(25)= 3.01, p < .05 
C) t(24)= 2.94, p < .01 
D) t(24)< significant 
A) t test(25)< significant 
B) t test(25)= 3.01, p < .05 
C) t(24)= 2.94, p < .01 
D) t(24)< significant

Question 17

It takes a slightly __________ extreme sample mean to get a significant result when using a t distribution than when using a normal curve. (more or less)

Accepted Answer

The answer of It takes a slightly __________ extreme sample...

Question 18

There is an entire family of t distributions that vary in shape according to the degrees of freedom used to estimate the population variance. However, for any particular degrees of freedom, there is/are only _____ t distribution (s).

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
A) 0 
B) 1 
C) 2 
D) 3

Question 19

If a sample has 45 people in it, the degrees of freedom used in the formula to estimate the population variance would be:

Accepted Answer

A) 452 
B) 45/2 
C) 44 
D)  .22 
A) 452 
B) 45/2 
C) 44 
D)  .22

Question 20

All of the following statements are true about t tests EXCEPT:

Accepted Answer

A) they involve hypothesis-testing procedures 
B) they are used when the population variance is unknown 
C) they are used when the population variance is known 
D) they compare t scores from a sample to a comparison distribution called a t distribution 
A) they involve hypothesis-testing procedures 
B) they are used when the population variance is unknown 
C) they are used when the population variance is known 
D) they compare t scores from a sample to a comparison distribution called a t distribution

A sample has three individuals, with scores of 2, 3, and 4. What is the estimated population variance?

With a t test for dependent means, Population 2 will ordinarily have a mean of:

In a study with 10 degrees of freedom, what would be your cutoff score for a t distribution using a one-tailed test at the .05 level of significance?

It takes a slightly __________ sample mean to get a significant result when using a t distribution than when using a normal curve.

Which of the following is TRUE?

If Professor Juarez had 30 students in her class, and she wanted to test her hypothesis using the 5% level of significance, what cutoff t score would she use? (You should be able to figure this out without a table because only one answer is in the correct region.)

The _________ is assumed to be 0 when doing a t test using difference scores.

The t test for dependent means is also called a:

What is often a limitation of research using a repeated-measure design?

If 15 research participants take a pretest and a posttest with a mean change score of 1.5, and if the standard deviation of the comparison distribution is .5, what is the t score?

Student's t was created by __________.

In a t test for dependent means, the mean change score is 12 and the standard deviation of the distribution of means is 6. What is the t score?

Suppose the standard deviation she figures (the square root of the unbiased estimate of the population variance)is .85. What is the effect size?

The estimated effect size for a study using a t test for dependent means is the mean of the difference scores divided by the:

Which of the following is the most likely way for results of a t test for dependent means to be presented in a research article for a study with 25 participants?

It takes a slightly __________ extreme sample mean to get a significant result when using a t distribution than when using a normal curve. (more or less)

There is an entire family of t distributions that vary in shape according to the degrees of freedom used to estimate the population variance. However, for any particular degrees of freedom, there is/are only _____ t distribution (s).

If a sample has 45 people in it, the degrees of freedom used in the formula to estimate the population variance would be:

All of the following statements are true about t tests EXCEPT:

Displaying the Order in a Group of Numbers Using Tables and Graphs

The Mean, Variance, Standard Deviation, and Z Scores

Correlation and Prediction

Some Key Ingredients for Inferential Statistics: the Normal Curve, Sample Versus Population, and Probability

Introduction to Hypothesis Testing

Hypothesis Tests With Means of Samples

Making Sense of Statistical Significance: Effect Size and Statistical Power

The T Test for Independent Means

Introduction to the Analysis of Variance

Chi-Square Tests and Strategies When Population Distributions Are Not Normal

Applying Statistical Methods in Your Own Research Project

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Exam 8: Introduction to the T Test: Single Sample and Dependent Means

A sample has three individuals, with scores of 2, 3, and 4. What is the estimated population variance?

With a t test for dependent means, Population 2 will ordinarily have a mean of:

In a study with 10 degrees of freedom, what would be your cutoff score for a t distribution using a one-tailed test at the .05 level of significance?

It takes a slightly __________ sample mean to get a significant result when using a t distribution than when using a normal curve.

Which of the following is TRUE?

If Professor Juarez had 30 students in her class, and she wanted to test her hypothesis using the 5% level of significance, what cutoff t score would she use? (You should be able to figure this out without a table because only one answer is in the correct region.)

The _________ is assumed to be 0 when doing a t test using difference scores.

The t test for dependent means is also called a:

What is often a limitation of research using a repeated-measure design?

If 15 research participants take a pretest and a posttest with a mean change score of 1.5, and if the standard deviation of the comparison distribution is .5, what is the t score?

Student's t was created by __________.

In a t test for dependent means, the mean change score is 12 and the standard deviation of the distribution of means is 6. What is the t score?

Suppose the standard deviation she figures (the square root of the unbiased estimate of the population variance)is .85. What is the effect size?

The estimated effect size for a study using a t test for dependent means is the mean of the difference scores divided by the:

Which of the following is the most likely way for results of a t test for dependent means to be presented in a research article for a study with 25 participants?

It takes a slightly __________ extreme sample mean to get a significant result when using a t distribution than when using a normal curve. (more or less)

There is an entire family of t distributions that vary in shape according to the degrees of freedom used to estimate the population variance. However, for any particular degrees of freedom, there is/are only _____ t distribution (s).

If a sample has 45 people in it, the degrees of freedom used in the formula to estimate the population variance would be:

All of the following statements are true about t tests EXCEPT:

Displaying the Order in a Group of Numbers Using Tables and Graphs

The Mean, Variance, Standard Deviation, and Z Scores

Correlation and Prediction

Some Key Ingredients for Inferential Statistics: the Normal Curve, Sample Versus Population, and Probability

Introduction to Hypothesis Testing

Hypothesis Tests With Means of Samples

Making Sense of Statistical Significance: Effect Size and Statistical Power

The T Test for Independent Means

Introduction to the Analysis of Variance

Chi-Square Tests and Strategies When Population Distributions Are Not Normal

Applying Statistical Methods in Your Own Research Project

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