With a height of 63 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 66.5 in and a standard deviation of 1.3 in. a. what is the positive difference between johnson’s height and themean? 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 minus−2 and 2, is johnson’s height usual or unusual?