What are different sampling methods?
When selecting a test panel for research, there are a number of different sampling methods. This research may include testing either the theory or a specific product, conducting an opinion, or any other research to cover a particular group as a whole. This group is known as a population, although it can include any type of group, not just the citizens of one country. This is known as a study of the census. For most populations, such as "all in China at the age of 65 or more," it is impossible to question or test everyone, so a group of samples must be selected. Different ways of selecting these participants are known as sampling methods. In the probability sampling method, everyone has a known probability that it will be selected, although this probabilism may differ from man to person. In a method of sampling of samples, some people do not have a chance to be selected because participants are selected from the specified parts of the population. It can be more comfortable, but comes at the price: unlike VThe zorking of probability that did not affect the sampling makes it impossible to estimate exactly how a group of samples represent the entire population.
The easiest form of probability sampling is a random selection of people from the list of the entire population. Variations of this method, systematic sampling, involves the selection of people at fixed intervals along the list, such as each hundred persons. Both of these sampling methods were rolled because the resulting group of samples may not represent the composition of the population. For example, a group of samples may have three children and seven adults, which is obviously not representative if the whole population is 20% of children and 80% of adults.
This can be solved by stratified sampling in which the population is divided into specific groups that share common factors and participants are selected from these groups in the appropriate conditions. In the above example, scientists randomly choose two people fromList of all children and eight people from the list of all adults. Naturally, this can be widespread to cover other types of group, for example by sex to form a group of samples that reflect the entire population more precisely.
The simplest forms of non -life sampling are called comfort sampling. Scientists simply choose participants who are the easiest to catch. Obviously, there is a strong risk that it will be very unrepresentative for the population. For example, if scientists knock on the door during the day, they will be less likely to be full -time participants.
Sampling quota combines stratified and sampling and usually includes research staff who are going to find participants who fill quotas. In the above example, scientists can knock on the door until they have spoken to two children and eight adults. Although this method means that a group of samples is in the right dimensions, the selection process makes it impossible to know howis representative. In our example, there may be eight adult unemployed, which would cause them not to represent the views of the entire population on the benefits of social security. For this reason, the sampling of quotas is classified as a type of sampling of harshness.