Chapter 17, Problem 46E

Exercises 45 through 48 refer to the following: As part of a research project, the blood pressures of 2000 patients in a hospital are recorded. The systolic blood pressures (given in millimeters) have an approximately normal distribution with mean $\mu =125$ and standard deviation $\sigma =13$.

a. Estimate the number of patients whose blood pressure was between 99 millimeters or higher.

b. Estimate the number of patients whose blood pressure was between 99 and 138 millimeters.