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.
Stratified Random Sampling: obtained by separating the population into mutually exclusive (only belong to one set) sets, or stratas, and then drawing simple random samples (a sample selected in a way that every possible sample with the same number of observation is equally likely to be chosen) from each stratum.
Basically in a stratified sampling procedure, the population is first partitioned into disjoint classes (the strata) which together are exhaustive. Thus each population element should be within one and only one stratum. Then a simple random sample is taken from each stratum, the sampling effort may either be a proportional allocation (each simple random sample would contain an amount of variates from a stratum which is proportional to the size of that stratum) or according to optimal allocation, where the target is to have a final sample with the minimum variabilty possible. The main difference between stratified and cluster sampling is that in stratified sampling all the strata need to be sampled. In cluster sampling one proceeds by first selecting a number of clusters at random and then sampling each cluster or conduct a census of each cluster. But usually not all clusters would be included.
Answer is Quota sampling. Its one of the method of non-probability sampling.
It will be the same as the distribution of the random variable itself.
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.
Stratified Random Sampling: obtained by separating the population into mutually exclusive (only belong to one set) sets, or stratas, and then drawing simple random samples (a sample selected in a way that every possible sample with the same number of observation is equally likely to be chosen) from each stratum.
Basically in a stratified sampling procedure, the population is first partitioned into disjoint classes (the strata) which together are exhaustive. Thus each population element should be within one and only one stratum. Then a simple random sample is taken from each stratum, the sampling effort may either be a proportional allocation (each simple random sample would contain an amount of variates from a stratum which is proportional to the size of that stratum) or according to optimal allocation, where the target is to have a final sample with the minimum variabilty possible. The main difference between stratified and cluster sampling is that in stratified sampling all the strata need to be sampled. In cluster sampling one proceeds by first selecting a number of clusters at random and then sampling each cluster or conduct a census of each cluster. But usually not all clusters would be included.
cluster sampling, quota sampling, systematic sampling, stratified random sampling which one is correct?
Basically in a stratified sampling procedure, the population is first partitioned into disjoint classes (the strata) which together are exhaustive. Thus each population element should be within one and only one stratum. Then a simple random sample is taken from each stratum, the sampling effort may either be a proportional allocation (each simple random sample would contain an amount of variates from a stratum which is proportional to the size of that stratum) or according to optimal allocation, where the target is to have a final sample with the minimum variabilty possible. The main difference between stratified and cluster sampling is that in stratified sampling all the strata need to be sampled. In cluster sampling one proceeds by first selecting a number of clusters at random and then sampling each cluster or conduct a census of each cluster. But usually not all clusters would be included.
Answer is Quota sampling. Its one of the method of non-probability sampling.
It will be the same as the distribution of the random variable itself.
Stratified sampling allows for more precise estimates as it ensures that each stratum of the population is represented in the sample. It also helps in capturing the characteristics of different subgroups within the population, leading to improved accuracy of results. Additionally, stratified sampling can reduce the sampling error and increase the efficiency of the sampling process.
random sampling ,systematic sampling , self-selected , and there is one more i don't know
Simple random sampling = A process of selecting subjects in such a way that each member of the population has an equal likelihood of being selected; you can throw all your subjects into a hat and draw them out one by one, or assign each member a number and choose every fifth number to be a participant.Probability sampling=A sampling procedure in which the probability that each element of the population will be included in the sample can be specified; you have a specific number of subjects and you know that they have a 50/50 chance of being chosen, or because of an anomaly, they may only have a 20/100 chance of being chosen for the experiment.*Your teacher is being tricky however, because there are 4 basic types of Probability sampling and simple random sampling is one of them. Also are stratified, systematic and cluster sampling. All four fall under the general title of Probability Sampling (P.S.)!! P.S. is kinda like the category and the 4 types are just different ways to do the sample, each has their own "little differences" in how the data is collected and assigned.
It is called one-stage cluster sampling. If random samples are taken within the selected clusters then it is two-stage cluster sampling.
1. Simple Random Sampling (SRS) - For SRS, every element has an equal probability of being chosen. In fact, any pair, triplet, and so on of elements have an equal chance of random selection. Sometimes, SRS can have problems because the randomness of the sample does not represent the population. For example, a SRS of one hundred people will likely produce about fifty men and fifty women, but it's also possible that there will only be ten men and ninety women selected due to natural sampling variation. 2. Systematic Sampling - For this type of sampling, every nth element is sampled. For example, if names were to be sampled through systematic sampling, every tenth name would be picked from the telephone book. However, this type of sampling may result in an unrepresentative sample of the population. 3. Stratified Sampling - When a population has certain categories, samples can be purposely collected from each strata (category). For example, there may be different strata for age groups if the person sampling is interested in variations between differences in age. One problem with stratified sampling is that it requires a more expensive cost than simple random sampling or systematic sampling. 4. Convenience Sampling - This type of sampling involves drawing the easiest samples to reach from the population. This may include surveying customers outside of a grocery store. Because the sample is limited to a certain time/day, it is unrepresentative of the entire population.