Within the realm of research, the use of samples plays a critical role in extrapolating data about the broader population. The selection of these samples, when undertaken with precision, can significantly influence the credibility of the overall study. This guide provides an in-depth exploration of one such method known as clustre sampling. As part of our comprehensive methodology, we will delve into the intricate aspects of clustre sampling, aiding in the further understanding and application of this sampling technique.
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Clustre Sampling – In a Nutshell
- Clustre sampling involves dividing a population into groups, after which the researcher can choose clustres through simple random sampling.
- This form of sampling can be done in a single stage or through multiple stages.
- A key benefit of this form of sampling is that you will end up saving money and time, particularly if the population covers a wide geographical area.
Definition: Clustre Sampling
Clustre sampling is a form of probability sampling which involves dividing a population into multiple groups known as clustres. The researchers then pick a sample randomly from the clustres to get a new study sample. This method is often used to study large populations that are distributed over a large geographical area. Since clustre sampling involves the random selection of samples, it can be used to describe the entire population.
Conducting clustre sampling
Single-stage clustre sampling only involves choosing a sample from the available clustres, and the researcher has to use all the samples within the selected clustres. This form of sampling is used when the group is homogenous in such a way that the clustres represent the population. Let’s look at the stages to follow when conducting single-stage clustre sampling.
Step 1: Defining the population
In clustre sampling, the first step is to define the population or group of individuals from which the samples will be drawn. For example, the population may be high-school students in New York.
Step 2: Divide the population into clustres
Once you have defined the population, you should divide it into clustres. It is important to take this step extremely seriously as the quality of the clustres will determine the validity of the study. When making the clustres, you should take the following factors into consideration:
- The individuals in each clustre should be diverse enough to represent the population.
- The distribution of characteristics in the clustre should be similar to those of the population.
- In total, the clustres should cover the whole population under study.
- None of the individuals should be included in more than one clustre.
If the clustres don’t work as small representations of the population, the results may not be reliable or valid. The issue with single-stage clustre sampling is that it can be hard to create perfect clustres in practical research. This is because real-life clustres are naturally-occurring groups and will usually fail to represent the population. For example, when researching high-school students in a town, it can be hard to find schools that represent the entire population. In this case, you would have to pick a number of schools. Simple random sampling generally offers higher levels of validity than single-stage clustre sampling.
Step 3: Imitate simple random sampling
Now that you have the clustres, you should assign numbers to them and choose the clustres randomly. This is similar to how you would conduct simply random sampling, and it helps to eliminate bias in the researcher. If you are able to find clustres that represent the population, this stage will help improve the validity of your results as it involves using random number generators. Simple random sampling would also be great for clustres that don’t represent the entire population. This is because the researcher would be able to study the diverse characteristics of the population.
When studying high-school students in New York, you can use simple random sampling and will pick a number of schools in the city. The ideal sample size will vary depending on population size, desired confidence levels, and the desired margin of error.
Step 4: Collecting data
The final step involves the collection of data from every clustre selected. This can be done in various ways. You can use questionnaires, interviews, surveys, observations, documents, records, and focus groups. For example, when studying the performance of students in New York, the researcher can go through the results posted by students in the selected clustres.
Multi-stage clustre sampling
With multi-stage clustre sampling, the researcher has to follow these steps:
- Define the population and create clustres
- Allocate a number to each clustre and use simple random sampling to create a sample
- From the selected clustres, you can study a number of individuals instead of the entire clustre
Depending on the nature of the study, the researcher can create smaller and smaller clustres in multiple stages. This form of sampling is commonly applied when the researcher does not have the necessary resources to test entire clustres.
When studying the performance of high-school students in New York, a researcher can create clustres of all high schools in the city. They can then pick a number of schools through simple random sampling. After that, they can narrow down the samples to a few classes. If this is still expensive or infeasible to study, the researcher can randomly select individuals from the classes.
Pros and Cons of clustre sampling
| ✓ Pros | ✗ Cons |
| Since you only have to study a few clustres of the population, it is cheaper to use this research method to study large populations. | The researcher may be biased when creating the clustres, and this would affect the overall validity of the study. |
| As a researcher, you will be able to save on administrative and travel costs, especially if the population covers a wide geographical area. | Samples drawn using this method frequently have higher sampling errors. |
| This method increases the feasibility of the study as allows researchers to divide the population into homogenous clustres. | This form of sampling is a lot harder to plan when compared to other sampling methods. |
FAQs
In statistics, clustre sampling is a technique that involves dividing a population into smaller groups known as clustres. The researcher then randomly selects samples from the clustres and studies them to form conclusions about the entire population.
The three types of clustre sampling are single-stage, double-stage, and multi-stage clustre sampling. These types of sampling differ in the number of times samples are randomly selected.
In stratified sampling, researchers aim at creating groups that are relatively homogenous when compared to the population, and the groups need to be different from each other. On the other hand, clustre sampling aims at creating groups that represent the characteristics of the population, and the clustres need to be identical.
This method is commonly used in market research and is useful in cases where the researcher cannot get sufficient information about the population as a whole.
