The monthly electrical utility bills of all customers for the Far East Power and Light Company are known to be normally distribu
ted with mean equal to $87.00 a month and standard deviation of $36.00. If a statistical sample of n = 100 customers is selected at random, what is the probability that the average bill for those sampled will exceed $75.00? g
Given : The monthly electrical utility bills of all customers for the Far East Power and Light Company are known to be normally distributed with a mean
Standard deviation :
Sample size : n=100
Let X be the random variable that represents the electricity utility bill for a randomly selected month .
z-score :
For X = $75.00
Now, the probability that the average bill for those sampled will exceed $75.00 will be :-
Hence, the probability that the average bill for those sampled will exceed $75.00 =0.9996