Question

In a test of the effectiveness of garlic for lowering​ cholesterol, 44

subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes (before−​after)

in their levels of LDL cholesterol​ (in mg/dL) have a mean of 3.2 and a standard deviation of 16.7. Construct a 95​%

confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDL​ cholesterol?

What is the confidence interval estimate of the population mean μ​?

​(Round to two decimal places as​ needed.)

Answer 1

Given

n = 44 (large sample)

difference of means = 3.2

=16.7

95​% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment

{ -1.734535 , 8.134535 }

H0: difference of means = 0

H1:  difference of means > 0

Since 0 lies between the confidence interval.

so the confidence interval suggest that no effectiveness of garlic in reducing LDL​ cholesterol.

confidence interval estimate of the population mean

{ -1.73 , 8.13 }