Acertain test preparation course is designed to students improve their scores on the lsat exam. a mock exam is given at the beginning and end of the course to determine the effectiveness of the course. the following measurements are the net change in 6 students' scores on the exam after completing the course: 8,6,12,15,42,23 using these data, construct a 80% confidence interval for the average net change in a student's score after completing the course. assume the population is approximately normal. step 4 of 4 : construct the 80% confidence interval. round your answer to one decimal place.

(9.6, 25.7) is a 80% confidence interval for the average net change in a student's score after completing the course.

Step-by-step explanation:

We have n = 6, and s = 13.3367. The confidence interval is given by

where is the th quantile of the t distribution with n-1=5 degrees of freedom. As we want the 80% confidence interval, we have that and the confidence interval is where is the 10th quantile of the t distribution with 5 df, i.e., . Then, we have and the 80% confidence interval is given by (9.6, 25.7)

the answer is c

step-by-step explanation:

4 and 5)16.97 or 12√2

6)15.59 or 9√3

7)y = 15.59 or 9√3     x =27

8)17.80