A student is conducting their science experiment on the effect of caffeine on dogs. They have 3 groups of test subjects. The 1st group of dogs receives plain water. The 2nd group of dogs receives 10 mg of caffeine each. The 3rd group receives 50 mg of caffeine each. They will measure their activity levels by recording how long each dog runs without stopping after giving them the pills. What is the independent variable in this experiment? A. The amount of caffeine given B. The amount of dogs tested C. The amount of activity D. The dogs that receive water
AT&T 4:49 PM [email protected] FOUNDERS Education Program Levy Question 4 of 50: 2 Points A student is conducting their science experiment on the effect of caffeine on dogs. They have 3 groups of test subjects. The 1st group of dogs receives plain water. The 2nd group of dogs receives 10 mg of caffeine each. The 3rd group receives 50 mg of caffeine each. They will measure their activity levels by recording how long each dog runs without stopping after giving them the pills. What is the independent variable in this experiment? A. The amount of caffeine given B. The amount of dogs tested C. The amount of activity D. The dogs that receive water
The Correct Answer and Explanation is:
Correct Answer: A. The amount of caffeine given
Explanation:
In a scientific experiment, the independent variable is the factor that the researcher intentionally changes or manipulates to observe its effect on another variable. In this case, the experiment is designed to investigate how different amounts of caffeine affect the dogs’ activity levels. Therefore, the independent variable is the amount of caffeine given.
The student sets up three groups of dogs, each receiving a different amount of caffeine: one group receives plain water (which serves as a control), another receives 10 mg of caffeine, and the third receives 50 mg. These different levels of caffeine are purposely chosen and administered by the experimenter. This variation in caffeine dosage is the experimental condition being tested.
On the other hand, the dependent variable is what the experimenter measures as the outcome. In this experiment, the dependent variable is the dogs’ activity level, specifically how long each dog runs without stopping. The idea is to see if changing the amount of caffeine will lead to a change in activity.
The other choices are not correct because:
- B. The amount of dogs tested refers to the sample size and does not change across treatment groups.
- C. The amount of activity is the result being measured and is therefore the dependent variable.
- D. The dogs that receive water are part of the control group, not the variable being changed.
In conclusion, since the experiment is testing the effect of caffeine dosage on activity, the independent variable is the amount of caffeine given.
