Assume that blood pressure readings are normally distributed with a mean of 124124 and a standard deviation of 9.69.6. If 144144 people are randomly selected, find the probability that their mean blood pressure will be less than 126126.

Probability that their mean blood pressure will be less than 126 is 0.9938.

Step-by-step explanation:

We are given that blood pressure readings are normally distributed with a mean of 124 and a standard deviation of 9.6. Also, 144 people are randomly selected.

Let = mean blood pressure

So, ~ N( )

The z score probability distribution for sample mean is given by;

               Z = ~ N(0,1)  

where, = population mean

            = population standard deviation

            n = sample size = 144

So, probability that their mean blood pressure will be less than 126 is given by = P( < 126)

  P( < 126) = P( < ) = P(Z < 2.50) = 0.9938 {using z table}

Therefore, probability that their mean blood pressure will be less than 126 is 0.9938 .