If the monthly electrical utility bills of all customers for the Far East Power and Light Company are known to be distributed as a normal distribution with mean equal to $87.00 a month and standard deviation of $36.00, which of the following would be the largest individual customer bill that you might expect to find?
A) Approximately $811.00
B) About $195.00
C) Nearly $123.00
D) There is no way to determine this without more information.

Question

Quizplus · Accepted Answer

Given the normal distribution of the bills, the largest bill one might expect to find would be several standard deviations above the mean, but not as extreme as $811.00. A value around $195.00 is plausible as it is approximately 3 standard deviations above the mean ($87 + 3*$36 = $195), which covers 99.7% of the distribution according to the empirical rule.

If the Monthly Electrical Utility Bills of All Customers for the Far