Question

When doing an experiment, the experimenter wants increase the chances that subjects' characteristics, that could bias the results of the experiment, and reduce the validity of the findings, are equally distributed across the treatment groups. Which of the following procedures would the experimenter utilize to accomplish this purpose?

a) random assignment b) systematic assignment c) reliable assignment d) all of the above

Answer 1

Answer- Systematics assignment

Random assignment of the experimental units to treatment groups helps in reducing systematic bias and gives a representative sample from the population. In this each unit has an equal chance of being in a treatment group Hence, this is not the correct option.

Systematic assignment of the experiment units to treatment gives bias and less valid results. Since units are assigned to groups in a manner which would give results desirable to the experimenter. For example, in a quality assurance experiment, the manufacturer wants a lot of bulbs to get passed for sales. So he chooses only good one instead of choosing randomly. This gives less valid and biased results. So, this the correct answer.

Reliable assignment of the experiment units to treatment means if we go by the dictionary meaning of reliable which is proven, authenticate. So this means reliable assignment is authenticated assignments of units which are proven to be good from the previous experiment. But in some cases, the results obtained from this will be less valid as compared to the random experiment. It does provide good results.