Construct Confidence Intervals for a Mean Response
-When Constructing a Confidence

Multiple Choice

Construct Confidence Intervals for a Mean Response
-When constructing a confidence interval about the mean response of $y$ in a linear regression, the $t$ -distribution is used with _____degrees of freedom.

A) $n - 2$
B) $n - 1$
C) $\mathrm { n } + \mathrm { k } - 2$
D) $n _ { 1 } + n _ { 2 } - 2$