Author Question: A researcher wants to make sure that his experimental group and his control group are equivalent, so ... (Read 73 times)

Melani1276 · **on:** Jul 8, 2018

A researcher wants to make sure that his experimental group and his control group are equivalent, so he uses random sampling followed by random assignment to group.

What else must the researcher do to assure the consumers of his research that the groups were equivalent? (Select all that apply.)
a. Report the sameness or difference of potentially extraneous variables, using post hoc statistical testing.
b. Eliminate all other extraneous variables from the analysis.
c. Rebalance the samples, controlling for all potentially extraneous variables, by moving subjects back and forth until both groups have the same distribution of all variables.
d. Randomly assign the sample again, hoping for a better outcome the second time.
e. Report the sameness or difference of subgroups possessing unequal proportions of any potentially extraneous variable, with respect to the dependent variable.

Question 2

In which instances could bias in measuring embarrassment be decreased? (Select all that apply.)

a. Use more than only one way of collecting the data (such as a verbal response + an external rater).
b. Use more than only one question to elicit the response (such as YesNo + how much).
c. Use more than only one modality of measurement (such as YesNo + a physiologic instrument).
d. Hypnotize subjects, so that they give absolutely honest answers.
e. Replicate the study.

nathang24 · **Reply #1 on:** Jul 8, 2018

Answer to Question 1

ANS: A, E
The most effective strategy for achieving equivalence is random sampling followed by random assignment to groups. However, this strategy does not guarantee equivalence. Even when randomization has been used, the researcher must examine the extent of equivalence by measuring and comparing characteristics for which the groups must be equivalent. This comparison is usually reported in the description of the sample.

Answer to Question 2

ANS: A, B, C
Mono-operation bias occurs when only one method of measurement is used to assess a construct. When only one method of measurement is used, fewer dimensions of the construct are measured. Construct validity greatly improves if the researcher uses more than one instrument. It is often possible to apply more than one measurement of the dependent variable with little increase in time, effort, or cost. In monomethod bias, the researcher uses more than one measure of a variable, but all the measures use the same method of recording.