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to the U.S. Energy Information Association (eia.gov), the mean electricity consumption per year For a household in the U.S. is 10400 kWh (kWh = kilowatt-hours = kilowatt * hours, it is how you get billed for electricity) with a standard deviation of 2400kWh. Let X = annual electricity consumption, in kWh, of a household and assume

X ~ N(10400, 2400).


1) What percentage of American homes consume between 8000 kWh and 9000 kWh of electricity a year?

Create a new sketch that shows the distribution of X and a shaded region

corresponding to the percentage you find (be sure to label 8000, 9000,and μ on your sketch).

 Apr 11, 2019

8000 is one standard deviation below the mean of 10400                        z-score = .1587

9000 is  1400/2400 =.58 standard deviations below the mean              z-score ~~ .2810


.2810 - .1587 = .1223          12 % of households are between 8000 and 9000 kwh consumption



I'll leave the graphing to you.....

 Apr 11, 2019

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