Question

In a test of effectiveness of garlic for lowering cholesterol, 43 subjects were treated with garlic in a processed tablet form. The changes in their levels LDL cholesterol (in mg/dL) have a mean of 3.2 and standard deviation of 16.3.

a.) contract 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?

b.) What is the confidence interval estimate of the population mean μ?

___mg/dL < μ < mg/dL

What does the confidence interval suggest about the effectiveness of the treatment ?

Answer 1

Solution:

Data Given:

n = 43 (number of subjects )

a)

confidence interval for mean is given by

for a 95% confidence interval, Z = 1.96

Substituting the values from the data given we get

solving this further we get

Thus -1.67 mg/dL < mean < 8.072 mg/dL

b)

since the confidence interval contain zero(0), the garlic was ineffective in reducing the LDL cholesterol.

i.e Garlic treatment did not effect the cholesterol level.