Population definition[ edit ] Successful statistical practice is based on focused problem definition. In sampling, this includes defining the population from which our sample is drawn. A population can be defined as including all people or items with the characteristic one wishes to understand.
GO Sampling Sampling is a fundamental aspect of Statistical samplingbut unlike the other methods of data collection, sampling involves choosing a method of sampling which further influences the data that you will result with. There are two major categories in sampling: Probability Sampling Under probability sampling, for a given population, each element of that population has a chance of being picked to part of the sample.
This is possible if we know the total number in the entire population such that we are then able to determine that odds of picking any one element. Probability sampling involves random picking of elements from a population, and that is the reason as to why no element has a zero chance of being picked to be part of a sample.
Methods of Probability Sampling There are a number of different methods of probability sampling including: Random Sampling Random sampling is the method that most closely defines probability sampling. Each element of the sample Statistical sampling picked at random from the given population such that the probability of picking that element can be calculated by simply dividing the frequency of the element by the total number of elements in the population.
In this method, all elements are equally likely to be picked if they have the same frequency.
Systematic Sampling Systematic sampling is the method that involves arranging the population in a given order and then picking the nth element from the ordered list of all the elements in the population.
The probability of picking any given element can be calculated but is not likely to be the same for all elements in the population regardless of whether they have the same frequency.
Stratified Sampling Stratified sampling involves dividing the population into groups and then sampling from those different groups depending on a certain set criteria. For example, dividing the population of a certain class into boys and girls and then from those two different groups picking those who fall into the specific category that you intend to study with your sample.
Multistage Sampling Multistage sampling involves use of more than one probability sampling method and more than one stage of sampling, for example for using the stratified sampling method in the first stage and then the random sampling method in the second stage and so on until you achieve the sample that you want.
Probability Proportional to Size Sampling Under probability proportional to size sampling, the sample is chosen as a proportion to the total size of the population. It is a form of multistage sampling where in stage one you cluster the entire population and then in stage two you randomly select elements from the different clusters, but the number of elements that you select from each cluster is proportional to the size of the population of that cluster.
Non-Probability Sampling Unlike probability sampling, under non-probability sampling certain elements of the population might have a zero chance of being picked. Methods of Non-Probability Sampling There are a number of different methods of Non-probability sampling which include: For example, if you walked down the street and sampled the first ten people you meet, the fact that they happened to be there is convenient for you but accidental for them which leads to the name of the method.
Voluntary Sampling Voluntary sampling, as the name suggests, involves picking the sample based on which elements of the population volunteer to participate in the sample.
This is the most common method used in research polls. Snowball Sampling Snowball sampling is a method of sampling that relies on referrals of previously selected elements to pick other elements that will participate in the sample.
Sign up for free to access more statistics resources like. Wyzant Resources features blogs, videos, lessons, and more about statistics and over other subjects. Stop struggling and start learning today with thousands of free resources!Definition of statistical sample: Limited number of observations selected from a population on a systematic or random basis, which (upon mathematical manipulation) yield .
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Questions? Comments? Report Bugs in Applets. In statistics, quality assurance, and survey methodology, sampling is the selection of a subset (a statistical sample) of individuals from within a statistical population to estimate characteristics of the whole population.
Statisticians attempt for the samples to represent the population in question. Two advantages of sampling are lower cost and faster data collection than measuring the. Buy Survey Research & Sampling Edition (Statistical Associates "Blue Book" Series Book 7): Read 4 Kindle Store Reviews - yunusemremert.com The gold standard of statistical experiments is the simple random sample.
In such a sample of size n individuals, every member of the population has the same likelihood of being selected for the sample, and every group of n individuals has the same likelihood of being selected.