The two methods of obtaining the sample can be compared and discussed in relation to a more real situation. The exercise could be repeated with larger samples and the average age in each of the two large parties found. In fact two sub-populations consisting of the ages of the Conservative and the ages of the Labour supporters were also prepared and the average age in samples of a fixed size from these was found. In all cases it is sensible to record the results of the different students centrally and discuss them in class. There are clearly some practical difficulties with these experiments.
Preparation is time-consuming and bags of slips of paper tend to be awkward in use.
Ideally several bags are needed so that all students have a chance to draw several samples. As it is instructive to let students sample from normal populations I prepared an assignment on similar lines as follows. Guidance was given in class as to what size of sample and how many samples to take. This last part of the assignment is a variation on an example presented in many introductory texts and was found to be useful in giving students an understanding of the sampling process. In some instances there would be advantages in having all students do the same exercise.