Question

The accompanying summary data on total cholesterol level (mmol/l) was obtained from a sample of Asian postmenopausal women who were vegans and another sample of such women who were omnivores.

Diet	Sample Size	Sample Mean	Sample SD
Vegan	89	5.30	1.05
Omnivore	92	5.75	1.10

Calculate a 99% CI for the difference between population mean total cholesterol level for vegans and population mean total cholesterol level for omnivores. (Use μ_Vegan − μ_Omnivore. Round your answers to three decimal places.)

   ,  

(mmol/l)

Interpret the interval.

We are 99% confident that the true average cholesterol level for vegans is less than that of omnivores by an amount within the confidence interval.We are 99% confident that the true average cholesterol level for vegans is greater than that of omnivores by an amount within the confidence interval.    We cannot draw a conclusion from the given information.We are 99% confident that the true average cholesterol level for vegans is greater than that of omnivores by an amount outside the confidence interval.

Answer 1

The statistical software output for this problem is:

Two sample Z summary confidence interval: H, Mean of population 1 (Std. dev = 1.05) Hy : Mean of population 2 (Std. dev = 1.1) H - Hy: Difference between two means 99% confidence interval results: Difference ol 02 Sample mean Std.err. L. limit U limit 89 92 -0.45 0.15981181 -0.86164794 -0.038352059

From above output:, 99% confidence interval will be:

(-0.862, -0.038)

Interpretation: We are 99% confident that the true average cholesterol level for vegans is less than that of omnivores by an amount within the confidence interval.

Option A is correct.