Question 1120534: In a study to assess the effectiveness of garlic for lowering cholesterol, 60 adults were treated with garlic tablets. Cholesterol levels were measured before and after treatment. The changes in their LDL cholesterol (in mg/dL) have a mean of 7 and a standard deviation of 4.
(a) Construct a 90% interval estimate of the mean change in LDL cholesterol after the garlic tablet treatment. (Round the lower bound and upper bound of the confidence interval to two decimal places) Include description of how confidence interval was constructed.
(b) Describe the results of the study in everyday language.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! This is a paired t with df=59, xbar 7, and s=4
The 90% CI is the mean +/- t 0.95, df=59, *s/sqrt(n)
the interval width is 1.67*4/sqrt(60)=0.86
The 90%CI is (6.14, 7.86)
We don't know the exact value for garlic's lowering cholesterol, but we are 90% confident that the true interval is between 6.14 and 7.86. It's not a probability, because the parameter is either in the interval or outside it.
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