The researchers also examined the independent variable of gender but did not include this variable in the

Question:

The researchers also examined the independent variable of gender but did not include this variable in the final regression equation. Why do you think gender was not included in the final regression model?

Khan, Sobki, and Alhomida (2015) examined 75 patients to assess the association between fasting blood sugar (FBS) measured in mmol/l and glycosylated hemoglobin (HbA1c) levels measured as a percentage and reported the following regression equation, which can be used to estimate an HbA1C level from a FBS level.