According to the U. S. Energy Information Administration, the mean monthly household electric bills in the United States in 2007 was $99.70. Assume the amounts are normally distributed with a standard deviation of $20. Answer the following questions. (Use the z table, keep four decimal places for proportions, and keep two decimal places for bill amounts.) 1) What proportion of household electric bills are over $131.50?
2) What proportion of household electric bills are less than $80?
3) What is the probability that a randomly chosen household electric bill is between $85.50 and $111.50
4) What is the probability that a randomly chosen household electric bill is either higher than $105 or less than $90?
5) What household electric bill amount represents the most expensive 30% of household electric bills?

Consider how health insurance affects the quantity of health care services performed. suppose that the typical medical procedure has a cost of $160, yet a person with health insurance pays only $40 out of pocket. her insurance company pays the remaining $120. (the insurance company recoups the $120 through premiums, but the premium a person pays does not depend on how many procedures that person chooses to undergo.) consider the following demand curve in the market for medical care. use the black point (plus symbol) to indicate the quantity of procedures demanded if each procedure has a price of $160. then use the grey point (star symbol) to indicate the quantity of procedures demanded if each procedure has a price of $40. q d at p=$160 q d at p=$40 0 10 20 30 40 50 60 70 80 90 100 200 180 160 140 120 100 80 60 40 20 0 price of medical procedures quantity of medical procedures demand if the cost of each procedure to society is truly $160, the quantity that maximizes total surplus is procedures. economists often blame the health insurance system for excessive use of medical care. given your analysis, the use of care might be viewed as excessive because consumers get procedures whose value is than the cost of producing them.

Comprehensive illustrative problem: mira's store on february 1 20a4 mica delaman opened astore that sells school supplies her main customer are the students and teachers of happy students school that is situated in front of her store. mira wanted to know the financial position of mira's store. mira knew you were studying accounting. so she asked for . 1. to start her business mira's opened a checking account in the name of mira's store . the statement of account from the bank shows that the checking account has a balance of 31,535 of december 31,20a4

Alocal barnes and noble bookstore ordered 80 marketing books but received 60 books. what percent of the order was missing?