31) The tread life of a particular brand of tire is a random variable best described by a normal 31) distribution with a mean of 60,000 miles and a standard deviation of 2800 miles. What is the probability a particular tire of this brand will last longer than 57,200 miles? A) 0.2266 B) 0.7266 C) 0.8413 D) 0.1587 32) A study was conducted to determine if the salaries of librarians from two neighboring cities were 32) equal. A sample of 15 librarians from each city was randomly selected. The mean from the first city was $28,900 with a standard deviation of $2300. The mean from the second city was $30,300 with a standard deviation of $2100. Construct a 95% confidence interval for M1 - H2. A) (-2871, 567) B) (-2054, 238) C) (-4081, 597) D) (-3125, 325) 33) At a tennis tournament a statistician keeps track of every serve. The statistician reported that the 33) mean serve speed of a particular player was 101 miles per hour (mph) and the standard deviation of the serve speeds was 14 mph. If nothing is known about the shape of the distribution, give an interval that will contain the speeds of at least three-fourths of the player's serves. A) 87 mph to 115 mph B) 73 mph to 129 mph C) 59 mph to 143 mph D) 129 mph to 157 mph 34) In a recent survey of drinking laws, a random sample of 1000 women showed that 65% were in 34) favor of increasing the legal drinking age. In a random sample of 1000 men, 60% favored increasing the legal drinking age. Construct a 95% confidence interval for p1 - P2. A) (-2.153, 1.679) B) (-1.423, 1.432) C) (0.587, 0.912) D) (0.008, 0.092) 35) A student randomly selects 10 paperbacks at a store. The mean price is $8.75 with a standard 35) deviation of $1.50. Construct a 95% confidence interval for the population standard deviation, o. Assume the data are normally distributed. A) ($1.03, $2.74) B) ($0.43, $1.32) C) ($1.43, $2.70) D) ($1.76, $3.10) Solve the problem. 36) A machine has four components, A, B, C, and D, set up in such a manner that all four parts must 36) work for the machine to work properly. Assume the probability of one part working does not depend on the functionality of any of the other parts. Also assume that the probabilities of the individual parts working are P(A) = P(B) = 0.95, P(C) = 0.99, and P(D) = 0.91. Find the probability that the machine works properly. Round to the nearest ten-thousandth. A) 0.8131 B) 0.8935 C) 0.1869 D) 0.8559 37) A sample of 250 shoppers at a large suburban mall were asked two questions: (1) Did you see a 37) television ad for the sale at department store X during the past 2 weeks? (2) Did you shop at department store X during the past 2 weeks? The responses to the questions are summarized in the table. What is the probability that a randomly selected shopper from the 250 questioned did not shop at department store X? Round the the nearest thousandth. Shopped at X Did Not Shop at X Saw ad 115 35 Did not see ad 35 65 A) 0.14 B) 0.26 C) 0.6 D) 0.4