How do cluster sampling and stratified random sampling differ? O Cluster sampling allows groups to mix together, but stratified random sampling does not. O In cluster sampling, the sample must match the proportion of the groups in the population, but in stratified random sampling this is not necessary. O Stratified random sampling requires selection from each group proportional to their share of the population, but cluster sampling does not. Stratified random sampling allows groups to mix together, but cluster sampling does not