For all three
regression visualizations, SAS Visual Statistics creates two variables that contain prediction
information for each
observation in the
data set. After these variables are created, they can be used in any other
visualization, including the other predictive models.
To create the two new
variables, complete the following steps:
-
-
Click
in the upper right corner of the visualization and select
Derive Predicted Values.
-
In the
New Prediction Variables window, enter a name for the
Predicted Values and either the
Residual Values or
the
Probability Values.
Residual
Values are available for linear regressions and generalized
linear models.
Probability Values are available
for logistic regressions.
-
Click OK. The predicted values for the logistic regression appear in the Category variables
section. All other variables, including the predicted values for the
other models, appear in the Prediction variables
section.
Depending on the chosen visualization, the information contained in each variable
is slightly different.
Predicted Values
For linear regressions and generalized linear models, this is a
numeric value that is the value generated by the
regression model. Or, this is the value that would have been generated by the regression model if
the observation was scored by the model.
For logistic regressions, this is the decision generated by the logistic regression
based on the calculated probability and
Prediction cutoff property. All observations are classified into either the
event level of interest, not the event level of interest, or missing.
Residual Values
The computed residual for each observation. Available for the linear regression and
generalized linear model visualizations.
Probability Values
The computed probability for each observation. Observations with probability values
that are greater than or equal to the Prediction cutoff property are predicted to be in the event level of interest. Observations with probability
values that are less than the Prediction cutoff property
are considered to be not in the event level or interest. That is,
there is no prediction made regarding each individual measurement
level, only between the measurement level of interest and everything
else.