What is the difference between simple random sampling and stratified sampling in educational science research method?

Simple random sampling is to directly extract n elements from a population containing n elements according to the principle of equal probability to form a sample (n >: n). This method is simple and easy to learn, and the common method is drawing lots. However, this applies to the case where the overall unit is small.

Stratified sampling is to divide all elements into several types or levels according to certain characteristics or signs (such as age, gender, occupation or region, etc.). ), and using the first two methods to extract a sub-sample, all sub-samples constitute the total sample.

discrepancy

Simple random sampling operation is simple, but the total number is too large and the workload is too large.

Stratified sampling fully ensures the consistency of sample structure and population, and improves the representativeness of samples. It is not applicable when the overall difference is not obvious, and it needs to be used in combination with other sampling methods.