
Chapter 15
568
t
b
S
b
=
In case of multiple regression, this concept can be generalized and the t-statistic can be de ned as
The test statistic t for multiple regression
t
b
S
b
j
=
where b
j
is the slope of the variable j with dependent variable y holding all other independent
variables constant, S
b
j
the standard error of the regression coef cient b
j
, and b
j
the hypothesized
population slope for variable j holding all other independent variables constant.
The test statistic t follows a t distribution with n – k – 1 degrees of freedom, where k is the
number of independent variables.
The hypotheses for testing the regression coef cient of each independent ...