If g is a quadratic function with a positive leading coefficient and a vertex at (0,3), which statement is true? a. both of the functions f and g intersect the x-axis at exactly two points. b. both of the functions f and g intersect the x-axis at only one point. c. the function f intersects the x-axis at two points, and the function g never intersects the x-axis. d. the function f intersects the x-axis at two points, and the function g intersects the x-axis at only one point.

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