A quality engineer is curious about the thickness of the paint on the Model A cars produced by her company. Explain how she can obtain a reliable measure of the thickness of the paint, stating clearly the characteristics of the variable she should use.

You want to test the hypothesis that smoking cigarettes increases the risk of lung cancer. in your experiment, you take 100 people of various ages and genders for each of your groups. one group smokes. the other group does not smoke. the group that does not smoke is called the group