EXAMPLE 10.1

Relationship between BMI and physical activity. Decrease in physical activity is considered to be a major contributor to the increase in prevalence of overweight and obesity in the general adult population. Because the prevalence of physical inactivity among college students is similar to that of the adult population, researchers have tried to understand college students’ physical activity perceptions and behaviors.

In several studies, researchers have looked at the relationship between physical activity (PA) and body mass index (BMI).¹ For this study, each participant wore a FitBit Flex^TM for a week, and the average number of steps taken per day (in thousands) was recorded. Various body composition variables, including BMI in kilograms per square meter, kg/m², were also measured. We consider a sample of 100 female undergraduates.