Chapter 9.1, Problem 12E

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 (“Vegetarianism, Bone Loss, and Vitamin D: A Longitudinal Study in Asian Vegans and Non-Vegans,” European J. of Clinical Nutr., 2012: 75–82).

Diet	Sample Size	Sample Mean	Sample SD
Vegan	88	5.10	1.07
Omnivore	93	5.55	1.10

Calculate and interpret a 99% CI for the difference between population mean total cholesterol level for  vegans and population mean total cholesterol level for  omnivores (the cited article included a 95% CI). [Note:  The article described a more sophisticated statistical analysis for investigating bone density loss taking into  account other characteristics (“covariates”) such as age, body weight, and various nutritional factors; the resulting CI included 0, suggesting no diet effect.]