f98Key1b

# f98Key1b - Answer Key for Exam 1 ( Version B) 1. Since we...

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Answer Key for Exam 1 ( Version B) 1. Since we are testing that the average price of a movie ticket in Tokyo is more than seven dollars more expensive than NYC’s, we have a one-tailed test. Ho : µ 1 - µ 2 ≤ 7 Ha : µ 1 - µ 2 > 7 Ans. E 2. With a sample size of 40 and 32 we use the Z test statistic. Z* = [( 1 - 2 )-Do] / √(S 1 ²/n 1 + S 2 ²/ n 2 ). From the given information, [(23-14) - 7] / √(5 2 / 40 + 3 2 / 32 ) = 2.10. Ans. D 3. Looking up the given Z*=2.01 in the Z tables we get .4778 for the “inside” area. The p-value is the one-sided tail area in this case so p-value = (.5 - .4778) =.0222 Ans. B 4. The hypothesized mean time (= 8) is not included in the confidence interval ( 8.3 to 9.4 ). The decision is to reject Ho and conclude there is evidence the average warm-up period is not equal to 8 minutes. NOTE : 90% C.I. is related to a two-tailed test at the 10% significant level. Ans. D 5. A Type I error occurs if you reject Ho when in fact it is true (see page 273). In this case, Ho states “the average warm-up time is equal to 8 minutes.” So rejecting Ho is concluding the mean

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## This note was uploaded on 03/09/2011 for the course DSCI 3710 taught by Professor Dr.jay during the Spring '08 term at North Texas.

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f98Key1b - Answer Key for Exam 1 ( Version B) 1. Since we...

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