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 aprofessor, 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 25.2 with a standard deviation of 4.9, while the 200 students in group 2 had a mean score of 18.6 with a standard deviation of 3.3. Complete parts (a) and (b) below.

(a) Determine the 95% confidence interval for the difference inscores, 12. Interpret the interval.

The lower bound is ________

.

The upper bound is__________

(Round to three decimal places asneeded.)

Interpret the interval. Choose the correct answer below.

A.

There is a 95% probability that the difference of the means is in the interval.

B.

The researchers are 95% confident that the difference of the means is in the interval.

C.

The researchers are 95% confident that the difference between randomly selected individuals will be in the interval.

D.

There is a 95% probability that the difference between randomly selected individuals will be in the interval.

(b) What does this say aboutpriming?

A.

Since the 95% confidence interval does not containzero, the results suggest that priming does not have an effect on scores.

B.

Since the 95% confidence interval containszero, the results suggest that priming does have an effect on scores.

C.

Since the 95% confidence interval does not containzero, the results suggest that priming does have an effect on scores.

D.

Since the 95% confidence interval containszero, the results suggest that priming does not have an effect on scores.