Deck 9: Inferences About Variances

Question 1

Which of the following is an example of two dependent samples?

A) Number of text messages sent to college freshmen and the number of emails sent to the same group of college freshmen
B) Pretest scores of preschool children and posttest scores of the same group of children
C) Science test scores of boys and science test scores of girls
D) Weight of zoo animals in the San Diego Zoo and weight of zoo animals in the Central Park Zoo

Answer 1

B

Question 2

Which of the following is an example of two dependent samples?

A) Birth weight of boys and birth weight of girls
B) Number of hours worked of blue collar workers and number of hours worked of white collar workers
C) Salaries for first-year teachers and salaries for third-year teachers
D) Weight of individuals before starting a weight loss program and weight of the same individuals after starting a weight loss program

Answer 2

D

Question 3

Which one of the following procedures is recommended when the distribution is platikurtic?

A) Brown-Forsythe
B) O'Brien

Answer 3

B

Question 4

Which one of the following procedures is recommended when the distribution is mesokurtic?

A) Brown-Forsythe
B) O'Brien

Question 5

Which one of the following procedures is recommended when the distribution is leptokurtic?

A) Brown-Forsythe
B) O'Brien

Question 6

A researcher computes the O'Brien procedure and finds an F test statistic of 2.22 and an F critical value of 2.01. Which of the following can be determined?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 7

A researcher computes the O'Brien procedure and finds an F test statistic of 3.81 and an F critical value of 2.61. Which of the following can be determined?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 8

A researcher computes the Brown-Forsythe procedure and finds an F test statistic of 4.75 and an F critical value of 3.32. Which of the following can be determined?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 9

A researcher computes the Brown-Forsythe procedure and finds an F test statistic of 2.35 and an F critical value of 3.78. Which of the following can be determined?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 10

A researcher conducted the Brown-Forsythe procedure and reports an alpha level of .05 and p value of .80. Which of the following is a correct statement based on this information?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 11

A researcher conducted the Brown-Forsythe procedure and reports an alpha level of .01 and p value of .005. Which of the following is a correct statement based on this information?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 12

A researcher conducted the Brown-Forsythe procedure and reports an alpha level of .01 and p value of .10. Which of the following is a correct statement based on this information?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 13

A researcher conducted the O'Brien procedure and reports an alpha level of .10 and p value of .05. Which of the following is a correct statement based on this information?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 14

A researcher conducted the O'Brien procedure and reports an alpha level of .05 and p value of .20. Which of the following is a correct statement based on this information?

A) The variances of the groups are statistically different.
B) The variances of the groups are NOT statistically different.
C) There is not enough information to make a determination.

Question 15

A researcher wants to determine if the sample variance for the number of hours spent studying per week for a sample of college students is different than 15. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 16

A researcher samples high school seniors and wants to determine if the variance of college entrance exam scores for the seniors prior to completing a test taking course is lower than the variance of college entrance exam scores for the same group of seniors after completing a test taking course. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 17

A researcher samples cheerleaders and wants to determine if the variance of the number of cartwheels conducted during a football game prior to attending cheer camp is different than the variance of the number of cartwheels conducted during a football game after attending cheer camp. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 18

A researcher samples parents of charter school transfer students and wants to determine if the variance of their child's satisfaction with school prior to transferring to the charter school is lower than the variance of their child's satisfaction with school after transferring to the charter school. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 19

A researcher samples unemployed workers and wants to determine if the variance of depression scores for the unemployed prior to becoming unemployed is higher than the variance of depression scores for the unemployed after becoming unemployed. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 20

A researcher wants to determine if the variance of points scored by teams who have won a national championship differs from the variance of points scored by teams who have not won a national championship. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 21

A researcher wants to determine if the variance of the amount of entertainment costs for families who live in subsidized housing differs from the variance of the amount of entertainment costs for families who do not live in subsidized housing. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 22

A researcher wants to determine if the variance of price of cars bought by males differs from the variance of the price of cars bought by females. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 23

A researcher wants to determine if the variance of salary of assistant professors differs from the variance of salary of associate professors. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 24

A researcher wants to determine if the sample variance for college tuition of a sample of college freshmen is different than $10,000. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 25

A researcher wants to determine if the sample variance for reading test scores of a sample of elementary aged children is different than 75. Which one of the following procedures is appropriate to test this?

A) Test for two dependent variances
B) Test for two independent variances
C) Test for a single variance
D) None of the above

Question 26

The following summary statistics are available for two dependent random samples:
s₁² = 36, s₂² = 16, n = 22, r₁₂ = .70.
Test the following hypotheses at the .05 level of significance:

Question 27

The following summary statistics are available for two dependent random samples:
s₁² = 100, s₂² = 225, n = 122, r₁₂ = .50.
Test the following hypotheses at the .05 level of significance:

Question 28

A random sample of 51scores is collected with a sample mean of 75 and a sample variance of 10. Test the following hypotheses at the .05 level of significance:

Question 29

A random sample of 9 scores is collected with a sample mean of 62 and a sample variance of 16. Test the following hypotheses at the .05 level of significance:

Question 30

A random sample of 5 scores is collected with a sample mean of 8 and a sample variance of 9. Test the following hypotheses at the .05 level of significance: