in a test of the effectivness of garlic for lowering cholest

in a test of the effectivness of garlic for lowering cholestrol, 47 subjects were treated with garlic in a proceesed form tablet. choleterol levels were meassured before and after the treatment. THe changes in their levels of LDL cholesterol in (mg/ml) have a mean of 4.4 and a standard deviation of 19.6

What is the best point estimate of the population mean net change in LDL cholesterol after the garlic treatment ? ___mg/dl

B) construct a 90% confidence interval estimate of the mean net change in LDL cholersterol after the garlic treatment

__mg/dl<M<__mg/dl

Solution

(A) best point estimate =4.4

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(B) Given a=1-0.9=0.1, Z(0.05) = 1.645 (from standard normal table)

So the lower bound is

xbar - Z*s/vn =4.4 -1.645*19.6/sqrt(47) =-0.3029791

So the upper bound is

xbar + Z*s/vn =4.4 +1.645*19.6/sqrt(47)=9.102979