The drama teacher wants to determine whether more students at the school would attend a comedy or a musical performance. Select all the following that would NOT the drama teacher draw conclusions about which performance more students would attend. A. Students who do not act.
B. Every 4th student selected from an alphabetical list of all students at the school.
C. Students who are in drama club.
D. Students who are in theater class.
E. The same number of students from each grade whose names are randomly selected from a hat.

Researchers are conducting experiments to determine the role of alcohol in the development of depression. after the study is complete, they determine that the relative risk of developing depression is 1.55 with a 95 % ci of 1.2 -1.9. each group is then divided into nonsmokers and smokers. the relative risk for the nonsmokers is 1.12 with a 95% ci of 0.87-1.37. the relative risk for the smokers is 1.7 with a 95 % cl of 1.5-1.9. what type of bias may affect this study? a. procedure bias b. recall bias c. selection bias d. confounding e. lead-time bias