The following simple model is used to determine the annual savings of an individual on the basis of his annual income and education.

Savings = α + β₁Edu + β₂Inc + ε

 The variable ‘Edu’ takes a value of 1 if the person is educated, and 0 otherwise;  and the variable ‘Inc’ measures the income of the individual (in $).

​Refer to the model above. The benchmark/reference group in this model is _____.