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Confidence Interval Multiple Choice

6. 100 employees were randomly selected and the mean time on work per week 41 hours with std deviation of 5 hrs. The 95% confidence interval for the mean time for all employees on work per week was:
(a)(40.02,41.98)
(b)(40.18,41.82)
(c)(1.88,8.12)
(d)(2.75,7.25)

For questions 7 to 9:
Let X be a random variable with mean 200 and std deviation of 25. Find the following x values:
7. The x value such that the area under the normal curve to the left of x is 0.6330.
(a)208.5
(b)241.125
(c) 241.75
(d) 250

8. The x value such that the area under the normal curve to the right of x is 0.5
(a)208.5
(b)241.125
(c) 241.75
(d) 250

9. The x value such that the area under the normal curve between 200 and x is 0.4525(x>200)
(a)208.5
(b)241.125
(c) 241.75
(d) 250

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Statistics MCQs

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