Question

Two researchers conducted a study in which two groups of students were asked to answer 42 trivia questions from a board game. The students in group 1 were asked to spend 5 minutes thinking about what it would mean to be a​ professor, while the students in group 2 were asked to think about soccer hooligans. These pretest thoughts are a form of priming. The 200 students in group 1 had a mean score of 25.5 with a standard deviation of 4​, while the 200 students in group 2 had a mean score of 18.4 with a standard deviation of 3.6. Complete parts ​(a) and ​(b) below.

​(a) Determine the 95​% confidence interval for the difference in​ scores, μ1−μ2.

The lower bound is:

The upper bound is:

​(b) What does this say about​ priming?

A.Since the 95% confidence interval contains​ zero, the results suggest that priming does not have an effect on scores.

B.Since the 95​% confidence interval does not contain​ zero, the results suggest that priming does have an effect on scores.

C.Since the 95​%confidence interval does not contain​ zero, the results suggest that priming does not have an effect on scores.

D.Since the 95​% confidence interval contains​ zero, the results suggest that priming does have an effect on scores.

Answer 1

Answer

Using TI 84 calculator

(A) press stat then tests then select 2 -sampTinterval

enter the data

x1 = 25.5, s1 = 4 , n1 = 200

x2 = 18.4, s2 = 3.6, n2 = 200

pooled: No

c-elevel = 0.95

press calculate, we get

lower bound = 6.35

upper bound = 7.85

(B) it is clear that the confidence interval is betweem 6.35 and 7.85, so the confidence interval does not include 0 in it. This shows that priming does have an effect on scores

option B