With a height of 64 in, Johnson was the shortest president of a particular club in the past century. The club presidents of the past century have a mean height of 71.5 in and a standard deviation of 2.8in.

a. What is the positive difference between Johnson's height and the mean?

b. How many standard deviations is that [the difference found in part (a)]?

c. Convert Johnson's height to a z score.

d. If we consider "usual" heights to be those that convert to z scores between -2 and 2, is Johnson's height usual or unusual?

The positive difference between Johnson 's height and the mean is?

The difference is ________ standard deviations. (Type an integer or decimal rounded to two decimal places as needed.)

The z score is? (Type an integer or decimal rounded to two decimal places as needed.)

Is Johnson's height usual or unusual?