The required formulas are in Sample Means
I have one more question I don't get from my Homework
The life expectancy in the U.S is 75 with a standard deviation of 7 years. A random sample of 49 individuals is selected.
a. What is the probability that the sample mean will be larger than 77 years?
b. What is the probability that the sample mean will be between 73.5 and 76 years?
Thank you
The required formulas are in Sample Means