According to the Center for Disease Control, young adult women have an average systolic blood pressure of 114.8 with a standard deviation of 13.1. Systolic blood pressure for young adult women follows a normal distribution. Four young adult women were randomly selected, find the probability that their average systolic blood pressure is greater than 125.

P(xbar>125)=

For this problem, we were told that the distribution is normal. If the shape of the distribution was not stated, we would not have been able to use the normal distribution table to find the probability. What does the Central Limit Theorem tell us to do to be able to normalize the distribution?

a. increase the standard deviation
b. increase mean
c. increase sample size
d. can not be normalized

What is the rule of thumb for normalizing the sampling distribution of means?