Marcus wants to determine how age and weight are related to exercise preference in his town. He selects a simple random sample of 75 overweight individuals from

the 25- to 35-year age group and records their age, weight, and exercise preference (sports, Pilates/yoga, dancing, none). He also selects an independent simple

random sample of 50 normal weight individuals from the 40-to 50-year age group and records the same information. Which is the most important observation about

Marcus's plan?

-He should have selected the two age groups randomly instead of choosing them specifically

-He will be unable to tell whether a difference in exercise preference is related to a difference in age or to a difference in weight

-The plan is well conceived and should serve the intended purpose

-His samples are too small

-He should have used equal sample sizes