Question 1

A researcher is interested in testing whether explaining the processes of statistics helps increase trust in computer algorithms. He wants to test for a difference at the = 0.05 level and knows that some people may trust the algorithms less after the training, so he uses a two-tailed test. He gathers pre-post data from 36 people and finds that the average difference score is = 12.10 with a standard deviation of s_D = 17.39. Conduct a hypothesis test to answer the research question.

Group of answer choices

a. Reject the null. There is no evidence that there is a change in trust after the training.

b. Reject the null. There is evidence that there is an increase in trust after the training.

c. Fail to reject (retain) the null. There is no evidence that there is a change in trust after the training.

d. Fail to reject (retain) the null. There is evidence that there is an increase in trust after the training.

Question 2

How do you calculate difference scores in a dependent sample t-test?

Group of answer choices

a. None of the other answers.

b. Subtract one group standard deviation from another, resulting on one difference score for the data set.

c. Subtract the raw scores for each pair of scores, resulting in a new set of difference scores for all the pairs.

d. Subtract one group mean from another, resulting on one difference score for the data set.

Question 3

Calculate mean difference score for the following data:

Time 1	Time 2	XD
61	83	-22
75	89	-14
91	98	-7
83	92	-9
74	80	-6
82	88	-6
98	98	0
82	77	+5
69	88	-19
76	79	-3
91	91	0
70	80	-10

Question 4

Calculate the standard error of the mean difference from the following descriptive statistics: s₁ = 24, s₂ = 21, n₁ = 36, n₂ = 49

Question 5

Lots of people claim that having a pet helps lower their stress level. Use the following summary data to test the two-tailed claim that there is a different average stress level among pet owners (group 1) than among non-owners (group 2) at the .05 level of significance.

xbar₁ = 16.25, xbar₂ = 20.95, S₁ = 4.00, S₂ = 5.10, n₁ = 25, n₂ = 25

Group of answer choices

a. Fail to reject (retain) the null. There is no evidence that pets lower stress.

b. Reject the null. There is evidence that pets lower stress.

c. Fail to reject (retain) the null. There is evidence that pets lower stress.

d. Reject the null. There is no evidence that pets lower stress.