Within each stratum it is, but overall, it is not.
The main difference is that the way of selecting a sample Random sample purely on randomly selected sample,in random sample every objective has a an equal chance to get into sample but it may follow heterogeneous,to over come this problem we can use stratified Random Sample Here the difference is that random sample may follow heterogeneity and Stratified follows homogeneity
In a stratified sample, the sampling proportion is the same for each stratum. In a random sample it should be but, due to randomness, need not be.
The main difference between the quota and stratified sampling is that in the stratified sampling the researcher can not select the individuals to be included in the sample (he doesn't have control over who will be in the simple), but in the quota sampling the researcher has control over who will be in the sample (he can contact certain people and include them in the sample).
stratified random sampling is a sample(strata) that a same and hemogenieous in group and that a different and heterogenious in group
Stratified random sampling is a sampling scheme which is used when the population comprises a number of strata, or subsets, which are similar within the strata but differ from one stratum to another. One example is school children stratified according to classes, or salaries stratified by departments.A simple random sample may not have enough representatives from each stratum and the solution is to use stratified random sampling. Under this scheme, the overall sampling proportion (sample size/population size) is determined and a sample is drawn from each stratum which represents the same proportion.
Equal representation for all groups.
Stratified sampling
1 in 16. You have 4 coins. The sample space is 16, i.e. 24.
The sampling proportion may be used to scale up the results from a sample to that of the population. It is also used for designing stratified sampling.
Probabilty is a a fraction.
stratified sample
They have used Stratified Sample. Design because stratified sample is a sampling technique in which the researcher divided the entire target population into different subgroups, or strata, and then randomly selects the final subjects proportionally from the different strata. This type of sampling is used when the researcher wants to highlight specific subgroups within the population. So in this Research this technique is used by the researcher.