Answer
a) Nonexperimental. Experimental studies are characterized by the researcher changing the independent variable so that different research groups experience different levels of that variable. In this example, the researchers merely interview students, but they don't control the independent variable (Vitamin C levels).
b) Experimental. In this example, the researchers give one group a Vitamin C supplement and the other group a multivitamin without Vitamin C. Since they are changing the independent variable, this is an experimental study.
Work Step by Step
a) Nonexperimental. Experimental studies are characterized by the researcher changing the independent variable so that different research groups experience different levels of that variable. In this example, the researchers merely interview students, but they don't control the independent variable (Vitamin C levels).
b) Experimental. In this example, the researchers give one group a Vitamin C supplement and the other group a multivitamin without Vitamin C. Since they are changing the independent variable, this is an experimental study.
