I need help filling out the table and also can you show me step by step on how y

Question

I need help filling out the table and also can you show me step by step on how you get the answer. I'd like to understand how to solve the questions.

The average amount parents spent per child on back-to-school items in August 2012 was $704 with a standard deviation of $189. Assume the amount spent on back-to-school items is normally distributed. Place this information in the School Sheet in this workbook and use it to answer the following questions. Based on this information (and information in Questions 7-13), generate excel output in the given space on the School sheet in this workbook to answer the following questions. Each orange numerical answer cell below MUST reference Excel output cells in the School sheet Question 7 Find the probability the amount spent on a randomly selected child is greater than $344. Question 8 Find the probability the amount spent on a randomly selected child is less than $520 or greater than or equal to $971 Question 9 Find the probability the amount spent on a randomly selected child is less than or equal to $785. Question 10 Find the probability the amount spent on a randomly selected child is greater than $225 and less than $810. Question 11 Th probability is 0.87 that the amount spent on a randomly selected child is no less than what value? (Remember the label.) Question 12A Question 12B The probability is 0.34 that the amount spent on a randomly selected child will be between what two values equidistant from the mean? Find the lower endpoint using Excel. Use this lower endpoint and some math to find the upper endpoint. (Remember the label.)

Explanation / Answer

(7) P(X<344)=0.0284 ( =NORMDIST(344,704,189,1)

we need P(X>344)=1-P(X<344)=1-0.0284=0.9716

(8)we need P(X<520)+P(X>=971)=P(X<520)+(1-P(X<971)=0.1651+1-0.9211=0.244

(9)P(X<785)=0.6659

(10)P(225<X<810)=P(X<810)-P(X<225)=0.7125-0.0056=0.7069

(11)P(X<x)=0.87, then x=917 (=NORMINV(0.87,704,189))

(12)P(x1<X<x2)=0.34

P(X<x1)+P(X>x2)=1-P(x1<X<x2)=1-0.34=0.66

or, P(X>x2)+P(X<x1)=0.66 (  P(X>x2)=P(X<x1) equidistant)

or, 2P(X<x1)=0.66

or,P(X<x1)=0.33

or, x1=620.85

P(X>x2)=0.33 or P(X>x2)=1-0.33=0.67 and x2=787.14

(13) lower end point=mean-3*sigma=704-3*189=137

upper end point =mean+3*sigma=704+3*189=1271

mu 704 sigma 189.00 x P(X<x) 7 344.0 0.0284 8 520.0 0.1651 8 971.0 0.9211 9 785.0 0.6659 10 225.0 0.0056 10 810.0 0.7125 P(X<x) x 11 0.87 917 12 0.330 620.8564117 12 0.670 787.1435883

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