A health study reported that in one country, systolic blood preassure reading hav a mean of 123 and a standard deviation of 18. A reading above 140 is considered to be high blood pressure. Complete parts a through d below.
a. What is the z-score for a blood pressure reading of 140?
b. The proportion with high blood pressure is ?
c. What proportion of the populatin has systolic blood pressure in the range from 98 to 140?
d. Find the 90th percentile blood pressure readings.