# Question Video: Determine If a Sampling Scenario Is Stratified Random Sampling Mathematics

In a certain survey about the colleges that some high-school students wish to join, a sample of 2,000 students was randomly selected out of a population of 40,000. Is that considered to be stratified sampling?

01:06

### Video Transcript

In a certain survey about the colleges that some high-school students wish to join, a sample of 2,000 students was randomly selected out of a population of 40,000. Is that considered to be stratified sampling?

To answer this question, let’s remind ourselves of what we mean by stratified or layered random sampling. This is a sampling method we use when the population consists of nonoverlapping subdivisions or strata. To select a stratified random sample from a population, we take random samples from each stratum proportional to the size of that stratum within the population. In this example, we’re told that our population size is 40,000 and that a sample of 2,000 students was randomly selected. We have no information on whether or not the population was subdivided into strata. And so we must assume that the random sample of 2,000 students was selected directly from the population where there were no strata involved. We cannot then say that this involves stratified sampling. Our answer must then be no, this is not stratified sampling.