When will stratfied sampling be a stratified random sampling?
I think u got your question wrong There is Random Sampling; then within that there is Stratified Random Sampling. Random Sampling just means that every possible sample has an equal chance of being selected from the population – without following some fixed pattern. Stratified sampling involves selecting independent samples from a number of subpopulations, group or strata within the population. When the size of the sample in each stratum is taken in proportion to the size of the stratum – and then a random sample is taken, then that is Stratified Random Sampling. The second version could be Systematic Sampling when within each strata, there is a fixed pattern of sampling – every 10th house, or every 100th teenager, etc. Cluster Sampling is another random sampling method. The option to Random Sampling can be Purposive Sampling where some of the respondents are pre-identified. There could be strata within that. Trust this helps.
