Answer:
D) all of the above
Step-by-step explanation:
The two-independent sample t-test is used to evaluate the differences in the means of two independent groups to ascertain if there is indeed a difference in the population means. So, the population variance is unknown before this test is done. To carry out this type of test, the researcher should ensure that there are no similarities between participants in the two groups so that there would be no influences between the groups. The participants in the research should be randomly selected.
The participants are observed one time to ensure that the same conditions hold for both groups and that there is a balance in the research blueprint.