A recent study found that the life expectancy of a people li

A recent study found that the life expectancy of a people living in Africa is normally distributed with an average of 53 years with a standard deviation of 7.5 years. What proportion of people in Africa die before the age of 65? Round your answer to 2 decimal places.

Solution

Normal Distribution
Mean ( u ) =53
Standard Deviation ( sd )=7.5
Normal Distribution = Z= X- u / sd ~ N(0,1)                  
P(X < 65) = (65-53)/7.5
= 12/7.5= 1.6
= P ( Z <1.6) From Standard Normal Table
= 0.9452   ~ 0.95