Question

32. According to the records of an electric company serving the Boston area, the mean electricity consumption during winter for all households is 1650 kilowatt-hours per month. Assume that the monthly electric consumption during the winter by all households in this area have a normal distribution with a mean of 1650 kilowatt-hours and a standard deviation of 320 kilowatt-hours. The company sent a notice to Bill Johnson informing his that about 90% of the households use less electricity per month than he does. What is Bill Johnson's monthly electricity consumption (round to the nearest ten kilowatt-hour)?

Answer 1

I let & be the number og Households use electrically quer month P(xxx) = 0.90 we have to find Vale a' 9 = 0.90 P(x-4)*- P(Z <Z72 8(2 - 0.90 2 - 1650 :0.90 -> 320 P(2¢1.282) = $(12282) -0.90 -) From © & U-1650 = 1.282 2060-24 320 Jokacom's Monthy eteckicity comes onyntion ur per Month. és 2060.24 kilowatt-hour CS Scanned with CamScanner