HR practitioners are increasing performing gender pay audits to understand whether a gender gap exists at their company. Practitioners examine payroll data for evidence of a gender pay gap. An HR practitioner collects data on base pay ($), gender (0 = female and 1 = male), and age (years) for 405 employees at his company and stores these data in HR .

Source: Data extracted from Chamberlain, A., How to Analyze Your Gender Pay Gap: An Employer’s Guide, available at bit.ly/2td7h33.

Develop a multiple regression model that uses gender and age to predict employee base pay. Be sure to perform a thorough residual analysis. The HR practitioner suspected that there was a significant interaction between gender and age. Is there evidence to support the HR practitioner’s suspicion?