After the Heckman models were estimated, l was checked to
determine whether it was significant, and whether Heckman
correction was required for the existing data set. In the study, the
outcome equation refers to demand models for potatoes, peas,
green beans, strawberries and cherries. In demand models, the
dependent variable is the amounts of the fresh and frozen products
purchased, which are offered to the consumers from various price
sets.