Results
If you want to repeat the Multiple regression procedure, possibly to add or remove variables in the model,
then you only have to press function key F7. The dialog box will re appear with the previous entries (see p.
14).
In the results window, the following statistics are displayed:
Sample size: the number of data records n
Coefficient of determination: this is the proportion of the variation in the dependent variable explained by
the regression model, and is a measure of the goodness of fit of the model. It can range from 0 to 1, and
is calculated as follows:
explained variation
(Y
Y)
2
R
=
=
est
total variation
(Y
Y)
2
where
Y
are the observed values for the dependent variable,
Y
is the average of the observed values and
Yest
are predicted values for the dependent variable (the predicted values are calculated using the
regression equation).
R adjusted: this is the coefficient of determination adjusted for the number of independent variables in the
regression model. Unlike the coefficient of determination, R adjusted may decrease if variables are entered
in the model that do not add significantly to the model fit.
unexplained variation
/
k
(n
1)
R
1
=
adj
total variation
/
1)
(n
or
Y
(Y
)
2
est
1)
(n
R
1
=
adj
(Y
Y)
2
1)
k
(n
Multiple correlation coefficient: this coefficient is a measure of how tightly the data points cluster around
the regression plane, and is calculated by taking the square root of the coefficient of determination.
When discussing multiple regression analysis results, generally the coefficient of multiple determination is
used rather than the multiple correlation coefficient.
62
New Page 1