When two triangles are congruent, this means they have the same shape and the same size. To have the same shape, each angle must be congruent. To have the same size, each side length must be congruent. When you know two triangles are congruent you can say each corresponding part of congruent triangles is congruent. This is known as CPCTC.

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