Sample Exam G, pg 1 The string tension of Wilson Tennis Rackets is normally distributed with a mean of 63 pounds and a standard deviation of 2...

1.Dick’s Sporting Goods has received a few complaints that the string tensions of Wilson

rackets seem too high. The Bloomington store manager calculates a confidence interval

for the mean racket tension of Wilson rackets. He knows that the tension is supposed to

be 63 pounds, but is not aware of the population standard deviation. He measures the

tension of 36 rackets and calculates a standard deviation of 2.2 pounds. How many

rackets must he measure to be within 0.55 pounds of the mean at a 97% level of

confidence?

A. 57 rackets.

B. 61 rackets.

C. 76 rackets.

D. 82 rackets.

2.Remembering the store owner's sample of 36 rackets yielded a standard deviation of 2.2

pounds, what is the margin of error of a ninety-nine percent confidence interval based on

the 36 rackets he measured, to four decimals?

A. 0.8543 pounds

B. 0.8947 pounds

C. 0.9460 pounds

D. 0.9973 pounds