Exhibit 16-4 In a Laboratory Experiment, Data Were Gathered on the Life

Multiple Choice

Exhibit 16-4
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. = 36 + 0.8x₁ - 1.7x₂
Also provided are SSR = 60 and SST = 180.
-Refer to Exhibit 16-4. 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