Question 1086667
Nationwide, the average waiting time until a electric utility customer service representative answers a call is 210 seconds. The Gigantic Kilowatt Energy Company randomly sampled 30 calls and found that, on average, they were answered in 183 seconds with a population standard deviation of 30 seconds. Can the company claim that they are faster than the average utility at α = 0.05?
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Ho: u >= 210
Ha: u < 210 (claim)
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z(183) = (183-210)/(30/sqrt(30)) = -4.93
Reject interval:: z < -1.96
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Conclusion:: Reject Ho
Conclusion:: Accept the claim
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 Answer:
a. Yes, because the test value –4.93 falls in the critical region.
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Cheers,
Stan H.
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