A Palatable Introduction to and Demonstration of Statistical Main Effects and Interactions

Because concrete explanations in a familiar context facilitate understanding, we illustrate the concept of an interaction via a baking analogy to provide students with food for thought. The demonstration initially introduces the concepts of independent and dependent variables using a chocolate chip cookie recipe. The demonstration provides an opportunity to distinguish between the main effect of an ingredient and the interactions between ingredients on taste perception. Student performance on exam questions suggests that this demonstration effectively helps students understand the concept and interpretation of an interaction.