A Researcher Wished to Compare the Effect of the Different

Multiple Choice

A researcher wished to compare the effect of the different rates of stepping on volunteers' heart rates in a step-aerobics workout.A collection of thirty adult volunteers,fifteen women and fifteen men,were selected from a local gym.The men were randomly divided into three groups of five subjects each.Each group did a standard step-aerobics workout,with Group 1 at a low rate of stepping,Group 2 at a medium rate of stepping,and Group 3 at a rapid rate.The women were also randomly divided into three groups of five subjects each.As with the men,each group did a standard step-aerobics workout,with Group 1 at a low rate of stepping,Group 2 at a medium rate of stepping,and Group 3 at a rapid rate.The mean heart rate at the end of the workout for all the subjects was determined in beats per minute. A partial ANOVA table for these data is given below. What are the advantages of studying the two factors simultaneously in the same experiment?

A) It is more efficient to study two factors simultaneously rather than separately.
B) We can reduce the residual variation in a model by including a second factor thought to influence the response.
C) We can investigate the interaction between factors.
D) All of the above