Electricity bills: According to a government energy agency, the mean monthly household electricity bill in the United States in

2011

was

$109.77

. Assume the amounts are normally distributed with standard deviation

$22.00

. Use the TI-84 Plus calculator to answer the following.

(a) What proportion of bills are greater than

$137

?

(b) What proportion of bills are between

$85

and

$148

?

(c) What is the probability that a randomly selected household had a monthly bill less than

$119

?

Round the answers to at least four decimal places.