Given a continuous response (dependent, outcome) variable and a set of
of numerical explanatory variables,
the multiple linear regression model is characterized by three assumptions.
The population mean of within strata defined by the 's
follows a linear and additive pattern, i.e.
This will be referred to as the regression equation.
Note: In the following we will use as shorthand for the set of
variables, so we can right
for the left
hand side in the above. I'll also use the term -strata
to describe strata determined by a particular set of values .
The standard deviation of within particular -strata,
, is constant over all values of . We'll
simplify notation by calling this value .