How might gender, body size, and health account for some of the differences in breathing rates between students?

Gender: Males have larger airways than females, even after differences in body size (height) are taken into account. Thus, males can move more air per breath than females. We can expect males to have slightly lower breathing rates than females of similar size and fitness.

Body size: We will use height as our measure of body size. An increase in height is usually accompanied by an increase in chest volume and lung volume. Thus, we...

Gender: Males have larger airways than females, even after differences in body size (height) are taken into account. Thus, males can move more air per breath than females. We can expect males to have slightly lower breathing rates than females of similar size and fitness.

Body size: We will use height as our measure of body size. An increase in height is usually accompanied by an increase in chest volume and lung volume. Thus, we can expect taller individuals to have slightly decreased breathing rates than short individuals of the same gender and similar fitness levels.

Health: We will use physical fitness as our measure of health. An increase in physical fitness results in a more efficient cardiovascular system. Thus, we can expect the heart rate of a physically fit individual to be lower than that of a physically unfit individual of the same height and gender.

You will likely find that the students in your class will have a wide range of heights and physical fitness, in addition to different genders. This will likely complicate your analysis, as you will find it hard to find truly matched pairs (e.g., two male students of the same height and different fitness levels, two female students of the same fitness level but different heights, etc.). Nevertheless, you may be able to see some of these trends in your data.