An experiment was carried out to study the effect of exercise on heart rate. The heart rates of 10 students were measured under three conditions: at rest, just before exercise (in anticipation of exercise), and immediately after running on a treadmill for two minutes. The data collected is shown in the table below:
| Student | Heart rate at rest (bpm) | Heart rate just before exercise (bpm) | Heart rate after exercise (bpm) |
|---|---|---|---|
| Liam | 70 | 75 | 135 |
| Emma | 82 | 85 | 142 |
| Noah | 68 | 72 | 125 |
| Olivia | 75 | 55 | 130 |
| Ava | 80 | 84 | 140 |
| Sophia | 72 | 76 | 128 |
| Jackson | 65 | 71 | 118 |
| Isabella | 78 | 82 | 137 |
| Lucas | 69 | 73 | 122 |
| Mia | 71 | 77 | 133 |
Calculate the average (mean) heart rate for the students after exercise. Show your working.
Identify the student who has an anomalous result in the data for heart rate just before exercise.
Suggest why most students' heart rate just before exercise is higher than their resting heart rate.
State two variables that must be controlled in this experiment.
Trained endurance athletes, such as marathon runners, often have a much lower resting heart rate than the general population. Suggest why a low resting heart rate develops in these individuals.
