Exhibit 13-12
in a Laboratory Experiment, Data Were Gathered on the Life

question 43

Multiple Choice

Exhibit 13-12
In a laboratory experiment, data were gathered on the life span Y in months) of 33 rats, units of daily protein intake X1) , and whether or not agent X2 a proposed life extending agent) was added to the rats diet X2 = 0 if agent X2 was not added, and X2 = 1 if agent was added.) From the results of the experiment, the following regression model was developed.
$\hat { Y }$ =36+0.8X1 - 1.7X2
Also provided are SSR = 60 and SST = 180.
-Refer to Exhibit 13-12. From the above function, it can be said that the life expectancy of rats that were given agent X2 is

• A) 1.7 months more than those who did not take agent X2
• B) 1.7 months less than those who did not take agent X2
• C) 0.8 months less than those who did not take agent X2
• D) 0.8 months more than those who did not take agent X2

---

Definitions:

Cross Elasticity of Demand

A measure of how the quantity demanded of one good responds to a change in price of another good, indicating the degree of substitutability between the two goods.

Complements

Goods or services that are used together, so that the consumption of one enhances the consumption of the other.

Substitutes

Products or services that can replace each other in satisfying a consumer's needs or wants.

Monthly Consumption

The total amount of goods and services that consumers purchase and use within a month.