1. Dependent Variable EDV, ESV, and cardiac cycle length
2. Independent Variable level of physical activity (resting or exercise)
3. Controlled Variables age, weight, height, gender and health
4. What instrument was used to measure cardiac volumes? ECG, and MRI
5. Does the instrument that was used to measure cardiac volume use X-rays? Explain.
The MRI shows a 3D and 2D image of the heart and the ECG measures the rhythm of the heartbeat.