Question

The average price of a college math textbook is $172 and the standard deviation is $29. Suppose that 8 textbooks are randomly chosen. Round all answers to 4 decimal places where possible. a. What is the distribution of a? -N( 172 ,29 b. For the group of 8, find the probability that the average price is between $174 and $184.1330 c. Find the third quartile for the average textbook price for this sample size. S 191.56 * (round to the nearest cent) d. For part b), is the assumption that the distribution is normal necessary? O No Yes

Answer 1

Solution The average price of a college math textbook is $172 and standard deviation is $29. @ The distribution of INN(M. I am ă ~ N(M=172, 29 - 10.25 18 10.25) IN N(M=172, I2 = 10.25) ہن۔ * ③ P( 174252 184) = P( 174-172 10.25 L < 184-172 10.25 = P(0.22Z< 1,17) EP (201.17) - P(Z20.2) : 0-8790- 0.5793. 0.2997 7 -075 p(1746 L 1824) = 0.2997 1. e. The probability that average price between is Between $1th and $ 184 is © Third Quartie 74th percentile 0.75 p(xsx)= 0.75 Ze=0.6745 Too XEMI Z.*6=172+ (0.6745*10.25) = 178.9136 7 178,912 179 neccessary @ Yes the assumption of the distribution is normal