Exercise 5. z Score for pulse rates of Adults: Assume that adults have pulse rates (beats per minute) with a mean of 72.9 and a standard deviation of 12.3 (based on data from the National Health Examination). When this exercise question was written, the author's pulse rate was 48.

z=X

(5a) What is the difference between the author's pulse rate and the mean?

(5b) How many standard deviations is that [the difference found in part (a)?

(5c) Convert a pulse rate of 48 to a z score

(5d) If we consider usual pulse rates to be those that convert to z scores between -2 and 2, is a pulse rate of 48 usual or unusual? Explain your answer