A certain test preparation course is designed to help students improve their scores on the GRE 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 7 students' scores on the exam after completing the course: 6,0,8,−1,3,14,76,0,8,−1,3,14,7
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 1 of 4: Calculate the sample mean for the given sample data. Round your answer to one decimal place.
Step 2 of 4: Calculate the sample standard deviation for the given sample data. Round your answer to one decimal place.
Step 3 of 4: Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.
Step 4 of 4: Construct the 80% confidence interval. Round your answer to one decimal
Lower endpoint
Upper endpoint