Wendy is investigating differences in cardiovascular health between children who are involved in extra-curricular activities and those who are not. she decides to investigate only children who are average height and weight, with no existing heart conditions and no family history of obesity. wendy has employed which method for controlling the extraneous variable in her study?

Based on the description above, Wendy has employed in the method for controlling extraneous variable in her study with the use of comparing homogeneous subgroups by which she decides on investigating only the children who has the average height and weight, and also with no heart conditions and history of obesity in her study.

answer; a cost benefit analysis;

answer; form new memories;