Capella PSYC4700 Week 6 Quiz Latest 2023

PSYC4700 – Stat for Behavioral Sciences

Week 6 Quiz 1

Question 1

The estimated standard error in the t statistic uses the ______ to estimate the ______ when the population variance is unknown.                                          

a. sample variance; population variance

b. population variance; sample variance

c. standard error; sample variance

d. degrees of freedom; sample size

Question 2

State the critical value(s) for a t test using a .05 level of significance in the lower tail only: t(24).                  

a. ±1.711

 b. -1.711

c. ±2.064

d. -2.064

Question 3

A researcher selects a sample of 32 participants who are assigned to participate in a study with one group. What are the degrees of freedom for this test?                                           

a. 32

b. 30

c. 31

d. There is not enough information to answer this question.

Question 4

Computing a two-independent-sample t test is appropriate when                                          

a. different participants are assigned to each of two groups.

b. the population variance is unknown.

c. participants are observed one time in a given group.

 d. all of the above.

Question 5

A researcher finds that the mean difference in productivity between employees working the morning shift (n = 16) and the night shift (n = 10) is 5.0 units, and the estimated standard error for the difference is 2.7 units. If the null hypothesis states that there is no difference in productivity, then is this result significant at a .05 level of significance for a two-tailed test?                                               

a. Yes, this result is significant.

b. No, this result is not significant.

c. There is not enough information to answer this question.

d. None of the above

Question 6

A researcher reports that the effectiveness of a new marketing campaign significantly increased sales compared with the previous campaign strategy, t(49) = 2.562, p < .05. Use η 2 to interpret the effect size for this result.                                       

a. 12% of the variability in marketing effectiveness can be accounted for by the new marketing strategy.

b. 12% of the standard error can be accounted for by the effectiveness of the marketing strategy.

c. Marketing effectiveness shifted 0.12 standard deviations above the mean in the population.

d. 12% of the variability in marketing effectiveness can be accounted for by the new marketing strategy and 12% of the standard error can be accounted for by the effectiveness of the marketing strategy.

Question 7

Which of the following summarizes a t test that was significant and associated with a large effect size?  

a. t(22) = 3.02, p < .05, d = .36

b. t(30) = 1.03, p > .05, d = .20

c. t(60) = 1.76, p > .05, d = .45

 d. t(12) = 2.95, p < .05, d = .82

Question 8

Each of the following is an advantage for using the related-samples design, EXCEPT                                        

a. it can be more practical.

b. it minimizes standard error.

c. it increases the power of a research design.

 d. it increases the variability measured in a study.

Question 9

A researcher reports with 90% confidence that 31% to 37% of Americans believe in ghosts. What is the point estimate for this interval?                                     

a. 31%

 b. 34%

c. 37%

d. 31% to 37%

Question 10

A researcher concludes that stress levels are higher following a major versus a minor traffic accident (95% confidence interval [CI] 1.86-3.02). If the null hypothesis stated that there would be no difference (null hypothesis: µ = 0), then what is the effect size for this confidence interval?                                        

a. Between 1.86% and 3.02% of the variability in stress levels can be accounted for by type of traffic accident.

b. Ratings of stress shifted more than 1.86 points in the population.

 c. Ratings of stress shifted between 1.86 and 3.02 points in the population.

d. There is not enough information to answer this question.

Question 11

In a sample of 18 participants, a researcher estimates the 80% CI for a sample with a mean of M 1 – M 2 = 8.8 and an estimated standard error for the difference ( S M1 – M2) of 1.8. What is the lower confidence limit for this interval?                                      

a. 6.4

b. 7.0

c. 10.6

d. 11.2

Question 12

In a sample of 20 participants, a researcher estimates the 99% CI for a sample with a mean of M D = 3.7 and an estimated standard error for the difference scores ( S MD) of 0.2. What is the confidence interval at this level of confidence?                                         

a. 99% CI 3.5, 3.9

b. 99% CI 3.2, 4.2

 c. 99% CI 3.1, 4.3

d. There is not enough information to answer this question.

Question 13

Which type of error is used to compute the confidence interval for two independent samples selected from at least one population with an unknown variance?                                

a. standard error

b. estimated standard error

 c. estimated standard error for the difference

d. estimated standard error for the difference scores

Question 14

A researcher increases his level of confidence from 90% to 95%. What will happen to the precision of his estimate?                                        

a. The estimate will be more precise.

b. The estimate will be less precise.

c. The precision of his estimate will not change.

d. It depends on the size of the population.

Question 15

The smaller the level of confidence, the ______ precise the estimate.                                  

a. more

b. less

c. neither