We use the form ŷ = a + bx for the least-squares line. In some computer printouts, the least-squares equation is not given directly. Instead, the value of the constant a is given, and the coefficient...

We use the form

for the least-squares line. In some computer printouts, the least-squares equation is not given directly. Instead, the value of the constant
a
is given, and the coefficient
b
of the explanatory or predictor variable is displayed. Sometimes
a
is referred to as the constant, and sometimes as the intercept. Data from a report showed the following relationship between elevation (in thousands of feet) and average number of frost-free days per year in a state.

Notice that "Elevation" is listed under "Predictor." This means that elevation is the explanatory variable
x. Its coefficient is the slope
b. "Constant" refers to
a
in the equation