Question 131427: Pleas help: Dullco Manufacturing claims that its alkaline last forty hours on average in a certain type of portable CD player. Tests on a random sample of 18 batteries showed a mean battery life of 37.8 hours with a standard deviation of 5.4 hours. What is the test statistics? Okay, I got this far: n=80, u=37.8, o=5.4 but then I got confused!
I don't have an ISBN because it is an online course, please help, it's due by midnight. Thank you
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Dullco Manufacturing claims that its alkaline last forty hours on average in a certain type of portable CD player. Tests on a random sample of 18 batteries showed a mean battery life of 37.8 hours with a standard deviation of 5.4 hours. What is the test statistics? Okay, I got this far: n=80, u=37.8, o=5.4 but then I got confused!
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Ho: mu = 40 hrs
Ha: ?
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Test statistic:
Use a t-test
t(x-bar) = (x-bar - mu)/[s/sqrt(n)]
t(37.8) = (37.8-40)/5.4/sqrt(18) = -2.2*sqrt(18)/5.4 = -1.7284...
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Cheers,
Stan H.
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