Which of the following methods can be used in the design of a study to control for alternative explanations of the results?
A)random assignment to experimental groups
B)reducing sampling error by increasing the sample sizes for the various groups
C)reducing sampling error by defining the groups such that the variances for each group will be small
D)b and c
E)all of these

Question

Quizplus · Accepted Answer

Random assignment to experimental groups helps to control for alternative explanations by ensuring that individuals in each group are on average similar in all respects, including background characteristics that could affect the outcome. Increasing the sample size for each group reduces sampling error, making the results more reliable. Defining the groups in such a way as to reduce variance can also help to control for alternative explanations, as it means that the groups are more homogeneous and differences between them are more likely to be due to the treatment being tested. Together, these methods provide a strong basis for designing a study that can safely attribute observed effects to the treatment being tested, rather than to other factors.

Which of the Following Methods Can Be Used in the Design