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

2011

was

$110.1

. Assume the amounts are normally distributed with standard deviation

$18.00

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

(a) What proportion of bills are greater than

$131

?

(b) What proportion of bills are between

$81

and

$142

?

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

$110

?

Round the answers to at least four decimal places.

Part 1 of 3

The proportion of bills that are greater than $131 is .

Part 2 of 3

The proportion of bills that are between $81 and $142 is .

Part 3 of 3

The probability that a randomly selected household had a monthly bill less than $110 is .