Final answer:
The independent variable in the experiment is the amount of alcohol given to each subject. The dependent variable is the driving skill of the subjects. The control variable is kept constant throughout the experiment.
Step-by-step explanation:
In an experiment, the variable that the experimenter manipulates or controls is called the independent variable. In this case, the amount of alcohol given to each subject by the experimenter is the independent variable. It is the variable that is intentionally changed by the experimenter to observe its effect on the dependent variable.
The variable that is being measured or observed to see how it is affected by the independent variable is called the dependent variable. In this case, the dependent variable would be the driving skill of the subjects. It is the variable that is affected or influenced by the independent variable.
The control variable refers to a variable that is kept constant or unchanged throughout the experiment to ensure that it does not impact the relationship between the independent and dependent variables. The extraneous variable, on the other hand, refers to any variable that is not intentionally controlled or manipulated by the experimenter but could potentially affect the results of the experiment.