what is the z score?

Question

a health study reported that in one country systolic blood pressure readings have a mean of 121and a standard deviation of 17. a reading above 140 is considered to be high blood pressure. what is the z score for a blood pressure reading of 140

Answer 1

A z-score is the number of stadnard deviations above or below the mean a given value is.

Here, (140-121) / 17 = 1.12. 140 is 1.12 SD above 121.