Question

1. which variable is intentionally changed by the researcher in an experiment?

a. independent variable
b. random variable
c. control variable
d. dependent variable

Explanation:

In an experiment, the independent variable is the one the researcher manipulates (intentionally changes) to observe its effect on the dependent variable. Random variables are probabilistic, control variables are kept constant, and dependent variables are measured (not changed by the researcher). So the correct option is a.

Answer:

a. Independent variable