Question 919919: You have a coffee machine that fills 8 oz cups. You take a sample of 18 cups of coffee. Where should the mean be set so that the probability that the sample mean is more than 8 oz (ie, at least some cups overflow) is only 0.01? Assume that the standard deviation is known to be 0.15 oz.
0.99 is 2.3263 on the inverse normal table used by my instructor
I got 2.3263 x 0.15 + 8 = 8.349 oz Is that right? On my practice test it scored it wrong. Please help.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! You have a coffee machine that fills 8 oz cups. You take a sample of 18 cups of coffee. Where should the mean be set so that the probability that the sample mean is more than 8 oz (ie, at least some cups overflow) is only 0.01? Assume that the standard deviation is known to be 0.15 oz.
0.99 is 2.3263 on the inverse normal table used by my instructor
I got 2.3263 x 0.15 + 8 = 8.349 oz Is that right? On my practice test it scored it wrong. Please help.
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Try using the standard deviation for the the distribution
of sample means, i.e. 0.15/sqrt(18) = 0.0354
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Cheers,
Stan H.
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