That's what statistical models do: they enable you to predict values and compare your model to reality. Your example is a classic regression model: predict the number of children as model of age, education, etc. The number of children is a response variable (dependent variable) which is estimated from the data according to the independent variables (age, education). You should read the Introduction to Statistical Modeling in the SAS/STAT documentation, and also the Introduction to Regression Modeling: SAS/STAT(R) 13.1 User's Guide
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