Explain why you are more likely to obtain a representative sample with proportionate stratified random sampling than with either stratified random sampling or simple random sampling

Question

What will be an ideal response?

Answer 1

In a proportionate stratified sample, each of the subgroups in the sample has exactly the same proportion as the corresponding subgroup in the population. For example, if 14% of the population is between 30 and 39 years old, then exactly 14% of the sample will be in this same age range. Thus, the composition of the sample exactly matches the composition of the population. A stratified random sample has equal representation from each of the specified subgroups. For example, if there are four subgroups in the population, then each will form 25% of the sample. However, the subgroups are probably not equally represented in the population. For example, one group may comprise only 10% of the population but will still make up 25% of the sample. Thus, the composition of the sample does not accurately represent the composition of the population. Finally, simple random sampling lets pure chance determine who is selected. As a result, a group that makes up 10% of the population can be severely overrepresented or underrepresented in the sample, depending entirely on chance. Thus, there is no guarantee that the composition of the sample will accurately represent the composition of the population.