Electric bills: According to a government energy agency, the

Last updated: 7/17/2022

Electric bills: According to a government energy agency, the mean monthly household electricity bill in the United States in 2011 was $109.99. Assume the amounts are normally distributed with standard deviation $17.00. (a) What proportion of bills are greater than $120? (b) What proportion of bills are between $80 and $135? (c) What is the probability that a randomly selected household had a monthly bill less than $105? Round the answers to at least four decimal places. The proportion of bills that are greater than $120 is