6.7 Interactions
An interaction effect, or statistical interaction, happens when the effect of an independent variable on the response changes depending on the value of another independent variable. An interaction can occur between two or more variables. Some examples are:
Education level and income impact: Higher education may have a stronger positive effect on income for one gender compared to the other, resulting in an interaction between education and gender.
Medication efficacy and age: A drug that works better for older individuals than younger ones.
Exercise and diet effects on weight loss: It could be that the diet’s effect on weight loss is small for people who do little or no exercise and large for people who do moderate exercise.
Temperature and humidity for crop growth: Some crops could thrive in hot and humid conditions, while others might perform better in cooler and less humid environments.
We have an interaction when the combined effect of two or more variables...
