Question

Assume that blood pressure readings are normally distributed with a mean of 118 and a standard deviation of 6.4. If 64 people are randomly​ selected, find the probability that their mean blood pressure will be less than 120. Round to four decimal places. A. 0.9938 B. 0.8615 C. 0.9998 D. 0.0062

Answer 1

Answer:

Option A - 0.9938

Step-by-step explanation:

Given : Assume that blood pressure readings are normally distributed with a mean of 118 and a standard deviation of 6.4. If 64 people are randomly​ selected.

To find : The probability that their mean blood pressure will be less than 120?

Solution :

The formula to find the probability is

$P(Z=X)=\frac{X-\mu}{\frac{\sigma}{\sqrt{n}}}$

Where, X is the sample mean

$\mu=118$ is the population mean

$\sigma=6.4$ is the standard deviation

n=64 is the number of sample

The probability that their mean blood pressure will be less than 120 is given by,

$P(Z$

$P(Z$

$P(Z$

$P(Z$

From the z-table the value of z at 2.5 is

$P(Z$

Therefore, Option A is correct.

The probability that their mean blood pressure will be less than 120 is 0.9938.