Homework: Chapter 7 homework Score: 0 of 12 pts 7.1.55 | | 30f 4 (0 complete) HW
ID: 3066072 • Letter: H
Question
Homework: Chapter 7 homework Score: 0 of 12 pts 7.1.55 | | 30f 4 (0 complete) HW Score: 0%0 of : , EQuestion Help At a certain coffee shop, all the customers buy a cup of coffee and some also buy a doughnut. The shop owner believes that the number of cups he sells each d normally distributed with a mean of 340 cups and a standard deviation of 23 cups. He also believes that the number of doughnuts he sells each day is independe the coffee sales and is normally distributed with a mean of 160 doughnuts and a standard deviation of 10. Complete parts a) through c). a) The shop is open every day but Sunday Assuming day-to-day sales are independent, what's the probability h'll ell over 2000 cups of coffee in a week? Round to three decimal places as needed.) Check Answe Enter your answer in the answer box and then click Check AnswerExplanation / Answer
Solution :Given that cups of coffee mean = 340,
cups of coffee standard deviation = 23
doughnut mean = 160
doughnut standard deviation = 10
=> weekly mean = daily mean*days open
= 340*6 = 2040 cups
=> var(weekly doughnuts) = daily standard deviation^2 *days open
= (23^2)*6 = 3174
=>weekly standard deviation = sqrt(var(weekly doughnuts)
= sqrt(3174) = 56.338
=>Z = (2000-2040)/56.338
=>Z = -0.710
=>P(x > 2000) = P(Z > -0.710) = 0.761
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