Question 386078: Please help with these homework questions:
A special diet should reduce cholesterol below 200. An SRS of 50 patients at risk had an average cholesterol of -x(mean)=192, with standard deviation s=21. Is this sufficient evidence that the diet is effective? Assume the distribution of the cholesterol for patients is approximately normal with mean u.
1)What is an appropriate hypothesis?
I said that the appropriate hypothesis is
Ho: u= 200, Ha: u> 200.
Is this hypothesis correct?
2)The appropriate degrees of freedom for this test are:
I said 51 by using f = [ s12/σ12 ] / [ s22/σ22 ]
Is this correct?
3)Based on the data, one sample t-statistic is?
I said 2.89 by using 200-192/21 x square root of (50/50-1)
Is this correct?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A special diet should reduce cholesterol below 200. An SRS of 50 patients at risk had an average cholesterol of -x(mean)=192, with standard deviation s=21. Is this sufficient evidence that the diet is effective? Assume the distribution of the cholesterol for patients is approximately normal with mean u.
1)What is an appropriate hypothesis?
Ho: u>= 200,
Ha: u< 200 (this is the claim; might as well make it a hypotheses)
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2)The appropriate degrees of freedom for this test are:
df = 49 because n = 50
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3)Based on the data, one sample t-statistic is?
t(192) = (192-200)/[21/sqrt(50) = -2.6937
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Cheers,
Stan H.
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