Definition
Let be a RSS of pooled (combined) regression’s, ‘s be RSS of regression in each group or time period, be the number of parameters estimated in each model, be the number of data of group , and , then the test Statistic is
Let be a RSS of pooled (combined) regression’s, ‘s be RSS of regression in each group or time period, be the number of parameters estimated in each model, be the number of data of group , and , then the test Statistic is