Question 273152: A business that repairs major appliances charges a flat fee and hourly amount plus the cost of any needed parts. They know that the time required to repair an appliance has a standard deviation of 0.25 hours. The mean depends on the type of appliance. To estimate the true mean time required to repair side-by-side refrigerators, they will take a random sample of 60 refrigerator repairs. If they want a 99% confidence interval, what will the margin of error in their estimate be? Your answer should be a number rounded to TWO decimal places
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A business that repairs major appliances charges a flat fee and hourly amount plus the cost of any needed parts. They know that the time required to repair an appliance has a standard deviation of 0.25 hours. The mean depends on the type of appliance. To estimate the true mean time required to repair side-by-side refrigerators, they will take a random sample of 60 refrigerator repairs. If they want a 99% confidence interval, what will the margin of error in their estimate be? Your answer should be a number rounded to TWO decimal places
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E = t*s/sqrt(n)
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E = invT(0.995 with df = 59)*0.25/sqrt(60) = 0.09
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Cheers,
Stan H.
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