travel

  Main and Interaction effects in factorial designs Consider the independent variables are ‘drug dosage’ and ‘gender’ and the dependent variable is ‘drug effectiveness’. Also, let drug dosage have 2 levels (low and high) and gender has 2 levels (male, female). After the experiment, we get the results like in the figure below.  Let the blue lines correspond to male and red with the female. We would like to ask the following questions? 1. Does dosage impact drug effectiveness? 2. Does gender impact drug effectiveness? 3. Does the interaction of dosage and gender impact drug effectiveness? What do you think (take 5 mins) To answer Q1, forget about the gender (colored lines) and consider only 1 independent variable (dosage) with the dependent variable like below, We can see that the mean effect of low dosage (green star ⭐) is indifferent from the mean effect of giving a high dosage suggesting that dosage doesn't have an effect on drug effectiveness.  To answer Q2, forget about the dosa