Question

An exercise physiologist classifies people – on the basis of their body mass index, heart rate, and lung capacity – as (a) above average in terms of fitness or (b) below average in terms of their fitness. He then directs the same people to walk on a treadmill, individually, at an increasing speed until they can no longer walk. He records the speed of the treadmill when a person maxes out on walking. He wants to know if there is a difference in the maximum walking speed for patients who have undergone knee replacement in the last ten years based on fitness level. A total of 100 people participated in the study.

1. What is the population and sample?
2. What are the dependent and independent variables? 
3. What is the research hypothesis? 
4. What are the levels of measurement for the dependent and independent variables?