a certain test preparation course is designed to help 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 5 students' scores on the exam after completing the course: 13,19,22,15,29 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.
