Question

In a test of the effectiveness of garlic for lowering​ cholesterol, 81 subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes​ (before minus​ after) in their levels of LDL cholesterol​ (in mg/dL) have a mean of 0.9 and a standard deviation of 2.25 . Use a 0.10 significance level to test the claim that with garlic​ treatment, the mean change in LDL cholesterol is greater than 0 . What do the results suggest about the effectiveness of the garlic​ treatment? Assume that a simple random sample has been selected. Identify the null and alternative​ hypotheses, test​ statistic, P-value, and state the final conclusion that addresses the original claim

Answer 1

null hypothesis: HO: μd		=	0
Alternate Hypothesis: Ha: μd		>	0
0.1 level with right tail test and n-1= 80 df, critical t=				1.292
Decision rule :reject Ho if test statistic t>1.292
	population mean μ=	0
	sample mean 'x̄=	0.900
	sample size   n=	81.00
	sample std deviation s=	2.250
	std error 'sx=s/√n=	0.2500
	test stat t ='(x-μ)*√n/sx=	3.600
	p value      =	0.0003

since test statistic falls in rejection region we reject null hypothesis
we have sufficient evidence to conclude that the mean change in LDL cholesterol is greater than 0