How do i find the value thats one standard deviation below the mean ? I'm stuck on this part of my homework

Question

Not sure how i'm suppose to solve this problem.

The following data are the distances between a sample of 20 retail stores and a large distribution center. The distances are in miles.

29; 30; 37; 40; 58; 67; 68; 69; 76; 81; 84; 95; 96; 96; 99; 106; 112; 127; 145; 150

Instructions: Find the value that is one standard deviation below the mean. (Must round the answer to one decimal place.)

Answer 1

So the steps you would have to take to complete this problem would be to first calculate the mean and standard deviation. Then subtract the standard deviation from the mean value, and that's how you get one standard deviation below the mean.