Question

What are the different forms of sampling?

Answer 1

Basically, there are two types of sampling that are probability and non-probability samples, which have many different subtypes.

Complete answer:
Probability Sampling:
It can be said as a form of random selection out of the sample space. This method consumes a lot of time and is an expensive method if put to use, but there is one advantage of using this method i.e., it guarantees the sample which would be the representative of the population (which can also be regarded as representative of the sample space).

Now Probability Sampling, is further divided into four types which are stated as below:
1) Simple random Sampling: As the name suggests it is a type of method in which every item has equal chance of getting selected. As the item is chosen randomly out of the sample space, we can also state it as Representative Sampling.
2) Systematic Sampling: This is the type of method which is calculated when total population is divided by the desired population size.
3) Stratified sampling: To complete the process we divide the total population into many different smaller groups, after these groups are formed, we then select samples on a random basis. These groups are made on some characteristics present in the sample population
4) Clustered Sampling: In this method also, we form groups based on similar characteristics. This type of sampling uses simple random sampling to choose the group of items from sample space.

Nonprobability Sampling:
In this type of sampling the items are chosen from the sample space on subjective judgement. In this type of sampling there is no guarantee that all items have equal chance of getting selected.
It is then also further divided into five parts as follows:
1) Convenience Sampling: In this type of sampling the items are selected directly from the sample space.
2) Consecutive Sampling: In this the selector selects a single item or a single group of items for sampling, it is the same as convenience sampling with a slight change for selecting purpose.
3) Quota Sampling: in this the selector chooses the items from the sample space on the basis of some specific qualities (i.e., which brings useful data that explains the whole space)
4) Purposive Sampling: In this type of sampling the items are chosen on the basis of the selector's idea of the sample space. As the selector has the idea only for selecting items out of sample space there is a very low chance of having an error due to which this process can be also termed as judgmental sampling.
5) Snowball Sampling: The items that have to be selected have characteristics which are difficult to identify in the sample space.

Note: All the above are different types of Sampling process which have little similarity in each one them, so before applying understand which type of sampling the question wants you to use.