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Unformatted text preview: Practice Questions  most of them are from previous years’ exams Question 1: As a check on the quality of the paper used for packaging, a random sample of ten pieces of paper is selected each hour from the previous hour’s production, and a strength measurement is recorded for each. Assume that the strength measurements are normally distributed with an unknown mean, but the standard deviation is known as 2 pounds per square inch. a. What is the probability distribution of the sample mean strength measurements? b. Assume the population mean strength is 21 pounds per square inch. What is the probability that the sample mean strength is less than 20 pounds per square inch? c. What is the population mean strength such that the probability of the sample mean strength less than 20 pounds per square inch equals to 0.01? Question 2: The following table presents the clubhead speed in mph ( C ) and the distance in yards ( D ) a golf ball travels for eight swings of the club by the same golfer. Swing 1 2 3 4 5 6 7 8 C 100 102 103 101 105 100 99 105 D 257 264 274 266 277 263 258 257 We have the following summary statistics: ¯ C = 101 . 875 , s C = 2 . 29518 , ¯ D = 266 . 75 , s D = 7 . 74135 , X ( C i ¯ C )( D i ¯ D ) = 116 . 75 a. Calculate the correlation coefficient and interpret the result in the context of this question. b. Apply the least squares method to predict the distance a golf ball travels when the clubhead speed is 104 mph....
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This note was uploaded on 12/22/2010 for the course MATHEMATIC Math 1131 taught by Professor Augustinewong during the Spring '10 term at York University.
 Spring '10
 AugustineWong

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