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 in their levels of LDL cholesterol​ (in mg/dL) have a mean of 5.5 and a standard deviation of 19.6 Complete parts​ (a) and​ (b) below. a. what is the best point estimate of the population mean net change in LDL cholesterol after the garlic treatment? b. 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?

Answer 1

(a)

Best point estimate of the population mean net change in LDL cholesterol = 5.5

(b)

= 5.5

s_d = 19.6

SE = s_d/

= 19.6/

= 2.9548

= 0.05

ndf = n - 1 = 44 - 1 = 43

From Table, critical values of t = 2.0167

Confidence Interval:

5.5 (2.0167 X 2.9548)

= 5.5 5.9590

= (- 0.4590 ,11.4590)

Confidence Interval:

- 0.4590   < < 11.4590

(c)

Since the interval contains 0, the confidence level does not suggest the effectiveness of garlic in reducing LDL cholesterol.