Chuck Wagon is very excited about the withinsubjects approac

Chuck Wagon is very excited about the within-subjects approach. \"Now Iâll never need to run large numbers of subjects again,\" he says. However Chuck has forgotten that within-subjects designs may be a) useless, b) impossible, c) confounded by order effects, or d) impractical when excessive subject time spent in an experiment makes data inaccurate. Give an example of each of these four objections.

Solution

a) useless : If we conduct testing the drugs, this is useless to conduct within subjects because the one drug is already used and no meaning to use the other drug on the same person.

b) impossible: In some situavtions it is impossible to conduct the same expereiment within the subjects twice. if the subjects are destructive or perisable after applying the treatment then it is impossible to use the same subject for other treatment.

c) confounded by order effects ;In the memory test, if first participants were asked to participate run and weightlifting before the test, secondly run and take the memory test.

The results in the second condition is better than first because subjects tired in the first instance where as in the second case running helps to the participants to be more active and would results in a better way. Thus confounding by order effects results.

d)impractical when excessive subject time spent in an experiment makes data inaccurate: while testing different types of teaching methods , it is impractical to use the different methods on the same subject.