Question 970729: In a random sample of 30 people who rode a roller coaster one day, the mean wait time is 46.7 minutes with a standard deviation of 9.2 minutes. In a random sample of 50 people who rode a Ferris wheel the same day, the mean wait time is 13.3 minutes with a standard deviation of 1.9 minutes. Construct a 99% confidence interval for the difference between the mean wait times of everyone who rode both rides.
A. (31.7, 35.1)
B. (30.5, 36.3)
C. (29, 37.8)
D. (28.7, 38.1)
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! In a random sample of 30 people who rode a roller coaster one day, the mean wait time is 46.7 minutes with a standard deviation of 9.2 minutes. In a random sample of 50 people who rode a Ferris wheel the same day, the mean wait time is 13.3 minutes with a standard deviation of 1.9 minutes. Construct a 99% confidence interval for the difference between the mean wait times of everyone who rode both rides.
sample mean difference:: 46.7-13.3 = 33.4
ME = 2.5857*sqrt[(9.2^2/30)+(1.9^2/50)] = 4.4
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99% CI:: 33.4-4.4 ; 33.4+4.4
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Ans: C
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Cheers,
Stan H.
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A. (31.7, 35.1):
B. (30.5, 36.3)::
C. (29, 37.8)
D. (28.7, 38.1)
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