Which of the following statements about good experiments is TRUE?
A. A good experiment must include all possible causal factors in one experimental group.
B. A good experiment must have an experimental group. A control group may be useful but is not critical.
C. A good experiment should include a potentially confounding factor in at least one group.
D. A good experiment includes replication by applying treatments to multiple experimental units.
The Correct Answer is A. A good experiment includes systematic variation for one or more hypothesized causal factors. is the correct option.
Why other options are incorrect?
A good experiment is characterized by two groups, a control group where one of the experimental conditions of interest is missing and a test group that has the condition.
The presence of both groups helps us dismiss the fact that the outcome of the experiment is not random but is correlated to the variable experimental condition that we are studying.
Similarly, repeating and reproducing the experiments is also necessary to reduce errors and get more confidence in the data.
Explanation:
because systematic variation is the discrepancy or error in observations caused by elements that are not under statistical control and hence TRUE in this case.