Soda Caffeine Experiment Scientists at a soft drink company want to test the effect of caffeine on heart rates,
They set up 3 groups of 50 people each.
All 150 people have their heart rates recorded before beginning the experiment,
Group 1 is given a non-caffeinated soda to drink.
Group 2 is given a regular caffeinated soda to drink,
Group 3 is given a highly caffeinated soda to drink,
The heart rate is recorded after each group has drank their soda,
What is the independent (or manipulated) variable in this experiment?
A. Amount of caffeine in soda
B. Change in heart rate
C. Amount of sugar in soda
D. Amount of movement by people before heart rate is recorded