Question

The following graphs show effects of variable 1 (medication) with 2 levels (treatment and control) as well as variable 2 (food) with 2 levels (consumption or none) on learning. Indicate whether medication effect, food effect, and/or interaction effect are present (meaning you have to evaluate the presence/absence of 3 separate effects). *Explain for each*

Learning No food With food Control Treatment

1.

2.

3.

Answer 1

1. In the above graph, let's consider the event where subjects are given only medication and the effect of medication is being observed on the subjects. Such an event is symbolised by blue line on the graph. The blue line shows a condition where only variable 1 can have effect on the subject. And truly so, there is an improvement in learning ability of the subjects who are administered medicines as compared to those who are not. Let regression of blue line give us a slope value (a).

2. Consider another situation where, food is given to the participants but medications have not been administered. This event is symbolised by a yellow line right above control. We can notice that learning outcomes in this condition is even lower as compared to condition mentioned in paragraph 1. We see that the yellow line is close to nil measured against y axis( which represents learning outcomes). Thus only giving food and no medication has negligible effect on learning outcome.

3. Consider the third event, where both variables have been administered- medication and food. It is depicted by yellow line in the paragraph. One can notice that the slope of this line (the value of which is, say 'b') is steep. Which makes b greater than a. The slope of yellow line is greater than blue one. Therefore, here learning outcomes are positively affected under the dual administration of variable 1 and 2 -medicine and food.