Assume that blood pressure readings are normally distributed with a mean of 115 and a standard deviation of 8. If 100 people are randomly selected, find the probability that their mean blood pressure will be less than 117.
A)0.9938
B)0.0062
C)0.8819
D)0.8615

Question

Quizplus · Accepted Answer

The probability that the mean blood pressure of 100 randomly selected people will be less than 117 is 0.9938. This is because the mean of the sampling distribution of the mean will be equal to the population mean, which is 115, and the standard deviation of the sampling distribution of the mean will be equal to the population standard deviation divided by the square root of the sample size, which is 8/sqrt(100) = 0.8. Therefore, the z-score for a mean blood pressure of 117 is (117 - 115) / 0.8 = 2.5, and the probability that the z-score will be less than 2.5 is 0.9938.

Assume That Blood Pressure Readings Are Normally Distributed with a Mean