Question

Joel noticed that when he runs, his heart begins to beat rapidly. Joe wants to do an experiment to see if his heart beats faster the longer he runs. Which is the best design for Joel‘s experiment?

a. Joel should get a group of people to run. Then he should ask them what their heart rates were after one minute.
b. Joe should ask someone to run at one speed. Then he should run the same amount of time at another speed.
c. Joel should run at a constant speed and measure his heart rate after different amounts of time has passed.
d. Joel should run different amounts of time at many different speeds and measured the heart rate during each run.

Answer 1

C

Explanation:

We can go through the process of elimination to solve the question.

A is incorrect because they are only running for a minute and the variation between time and heart rate cannot be measured.

B is incorrect because there are too many variables to account for and they are both running for the same amount of time.

D is incorrect because there are too many variables to account for and it is not a fair test as he is running at many different speeds (you can only change the independent variable which is the time).

Hence, C is the answer. It is a fair test as he is running at different speeds and keeping everything else the same.