AP Stats Midterm

What is the principle purpose of control in a randomized comparative experiment?

Isolating the effect of the treatment variable by keeping all other variables the same in the treatment groups

Control groups are used in experiments in order to accomplish which one of the following?

Limit the effects of variables other than the explanatory variable on the outcome

Which of the following is the most important reason for randomly assigning subjects to treatment groups in an experiment?

To create groups that are as similar as possible

The essential difference between an experiment and an observational study is that

an experiment imposes treatments on the subjects, but an observational study does not

The correlation coefficient measures

the strength of the linear relationship between two quantitative variables