On a coordinate plane, 2 trapezoids are shown. Trapezoid A B C D has points (negative 2, 4), (2, 4), (negative 3, 0) and (3, 0). Trapezoid E F G H has points (negative 1, 2), (1, 2), (negative 2, 0) and (2, 0). Derek tried to dilate the isosceles trapezoid ABDC with the center of dilation at the origin with a scale factor of 2. Check his work and complete the statements.

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