Suppose a new study is conducted in which there will be n 1 Caucasian subjects and n 2 African American subjects, where n 2 2n 1 How large should n 1 and n 2 be in order for the new study to have 90 power to detect a mean difference of 5 mg dL between the two groups, where a two sided test is condu...

For this problem we need to use the sample size formul ...

Suppose a new study is conducted in which there will be n 1 Caucasian subjects and n

Question:

Suppose a new study is conducted in which there will be n₁Caucasian subjects and n₂African American subjects, where n₂= 2n₁. How large should n₁and n₂be in order for the new study to have 90% power to detect a mean difference of 5 mg/dL between the two groups, where a two-sided test is conducted with Î± = .05?

Cardiovascular Disease

A study of genetic factors related to coronary heart disease (CHD) was performed as a substudy within the ARIC Study [20]. The data in Table 8.35 were provided by ethnic group for high-density lipoprotein (HDL) cholesterol (mg/dL).

Table 8.35: Mean HDL cholesterol (mg/dL) by ethnic group

African-American Caucasian 55.3 17.2 3167 Mean sd 51.1 16.8 9389