Beer and blood alcohol The example on page $182$describes a study in which adults drank different amounts of beer. The response variable was their blood alcohol content (BAC). BAC for the same amount of beer might depend on other facts about the subjects. Name two other variables that could account for the fact that $r^2=0.80.$

Beer and alcohol in the blood On page $182$, there is an example of a research in which participants consumed various amounts of beer. Their blood alcohol concentration was the response variable (BAC). BAC for the same amount of beer could be affected by their knowledge of the issue.

A regression line is a straight line that depicts the change in a response variable $y$ when an explanatory variable $x$ changes. By putting this $x$ into the equation of the line, you may use a regression line to predict the value of $y$ for any value of $x$

Take, for example, the instance of Beer and Blood Alcohol. The concentration of alcohol in the blood is measured by the blood alcohol content (BAC). As a rapid indicator of BAC, the researchers employed a number of beer cans. The BAC for the same amount of beer could be affected by various factors such as the subjects' body type and weight. The quantity of beer cans consumed and the BAC level have no causal relationship.