Jeffrey wants to lose weight by using caffeine to help with exercise. He asks himself, "Which
caffeine drink will raise the heart rate the most?"
He tries to test this out by comparing the heart
rates of his neighbors, 3 brothers who are
triplets. One of the brothers drinks Pepsi,
another drinks a double shot of espresso (which
is coffee with twice the normal amount of
caffeine) and a third brother drinks only water for
comparison
Jeffrey finds out that the triplet with the double
shot of espresso had the highest heart rate.
4. What is the independent variable for this experiment?
5. What is the dependent variable for this experiment?
6. Which type of drink can be considered the control group? The pepsi, espresso, or water?
7 Write down 3 constants that all 3 brothers should be doing the same for this experiment?

4. The amount of caffeine in the drinks

5. The heart rate of the participants of the experiments

6. Water

7. i) The volume of drink taken should be constant

ii) The frequency of taking their drink is constant

iii) The time of drinking by the brothers is constant

Explanation:

In the question, Jeffery intends to find the caffeine drink that will result in the heart rate increasing most

The variables (varieties) of drinks tested by Jeffery = Pepsi, espresso, and water

Drink variable arranged by the order of increasing Caffeine content are presented as follows;

Caffeine content of water < Caffeine content of Pepsi < Caffeine content of espresso

The triplet with the double shot of espresso = The triplet with the highest heart rate

4. The independent variable is the variable which is suspected to be the cause of the specified observation

Therefore, in the question, the independent variable are the drinks with different amount of caffeine

5. The dependent variable is the effect or the outcome of the independent variable

The dependent variable in the question is the heart rate of the subjects in the study

6. The control group is the independent variable or input that is expected to give the minimum effect or output compared to other independent variables in the study such that the control group does not contain the suspected cause of the observation or effect under investigation

The control group (or variable) in the question is water which does not contain caffeine

7. Three constants that all three brothers should be doing are;

i) The three brothers should be taking a constant or the same quantity of their preferred drink

ii) The frequency at which they take their drinks should be constant

iii) The time at which the brothers take the drink should be the same