SOLUTION: I need help with the following question please. A sociologist develops a test to measure attitudes about public transportation, and 27 randomly selected subjects are given the t

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Question 266356: I need help with the following question please.
A sociologist develops a test to measure attitudes about public transportation, and 27 randomly selected subjects are given the test. Their mean score is 76.2 and their standard deviation is 21.4. Construct the 90% confidence interval for the mean score of all such subjects. You may assume the scores are normally distributed.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A sociologist develops a test to measure attitudes about public transportation, and 27 randomly selected subjects are given the test. Their mean score is 76.2 and their standard deviation is 21.4. Construct the 90% confidence interval for the mean score of all such subjects. You may assume the scores are normally distributed.
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sample mean = xbar = 76.2
standard error = E = zs/sqrt(n)
E = [invT(0.95,df=26)*21.4/sqrt(27) = 1.7056*21.4/sqrt(27) = 7.0245..
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90% CI: 76.2-7.0245 < u < 76.2+7.0245
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Cheers,
Stan H.