In a study examining the effect of room illumination (low, medium, high) and room temperature (cold, warm, hot) on test performance, how many main effects are possible?
a. 9
b. 6
c. 2
d. 3
Answer: 2
In a study examining the effect of room illumination (low, medium, high) and room temperature (cold, warm, hot) on test performance, how many main effects are possible?
a. 9
b. 6
c. 2
d. 3
Answer: 2