A random sample of 13 students were asked how long it took them to complete a certain exam. The mean length of time was 123.9 minutes, with a standard deviation of 73.0 minutes. Find the lower bound of the 90% confidence interval for the true mean length of time it would take for all students to complete the exam.​

46

step-by-step explanation:

given

height = 168 cm

formula

height =2.47*f+54.13

solution

168 = 2.47f + 54.13             subtract 54.13 from both sides

168 - 54.13   = 2.47f             combine

113.87 = 2.47f                     divide by 2.47

113.87 / 2.47 = f                   combine

46.1 = f  

answer: 46 cm

example answer: "to determine if a sum is reasonable you can round each number to the nearest whole and compare the estimated sum to the actual sum."

hope this you and anyone else who needs the answer : ^)