Random Sampling

A sampling strategy in which each sample has an equal chance of being chosen is known as random sampling. A random sample is designed to be representative of the total population. When a sample does not precisely represent the population for some reason, this is known as a sampling error. In the field of research, random sampling is regarded as one of the most popular and straightforward data collection procedures (probability and statistics, mathematics, etc.). It allows for the collecting of unbiased data, allowing investigations to obtain unbiased conclusions.

Random sampling techniques meaning

There are four different types of random sampling methods:

1. Simple random sampling: To choose a sample, simple random sampling involves the use of randomly generated integers At the start, a sample frame, which is a list or database of all people in a population, is needed. You can then use Excel to generate a random number for each element and take the first n samples you require.

As an example, consider the table on the right as your sampling frame. You may then generate random integers for each element in the sample frame using software like Excel. If you require a sample size of three, you’d take samples with random numbers ranging from one to three.

2. Stratified random sampling: The first step in stratified random sampling is to divide a population into groups with comparable characteristics.

This strategy is used to ensure that different segments of a population are equally represented. It might make sense to utilize stratified random sampling to ensure that the perspectives of students in each department are evenly represented.

3. Cluster random sampling: The process of cluster sampling begins with the division of a population into groups or clusters. The fact that each cluster must be representative of the population distinguishes this method from stratified sampling. After that, you take a random sample of entire clusters.

If an elementary school had five different grade eight classrooms, cluster random sampling might be employed, with only one class picked as a sample.

4. Systematic random sampling: A typical strategy is systematic random sampling, which involves sampling every kth element. If you were conducting surveys at a mall, for example, you may survey every 100th person who walks through.

If you have a sampling frame, divide the frame size, N, by the desired sample size, n, to get the index number, k. To generate your sample, you’d pick every k’th element in the frame.

Random sampling formula and example

Consider a school with 1000 kids and a researcher who wishes to study 100 of them further. All of their names might be thrown into a bucket, from which 100 would be drawn. Not only does each person have an equal chance of being chosen, but because we know the sample size (n) and the population (N), we can easily compute the probability (P) of a specific person being chosen:

If a person can only be chosen once (i.e., after being chosen, the individual is withdrawn from the selection pool)-

P= 1- N-1/ N . N-2 /N-1

N-n / N-(n-1)

Canceling= 1- N-n / N

P= n / N

= 100 / 1000

=10%

If any chosen person is returned to the selection pool (i.e., they can be chosen more than once)

P=1-(1-1/N)ⁿ=1-(9991000)100

=0.0952≈9.5%

Random Sampling’s Advantages

Random Sampling’s Advantages given below

• It allows you to undertake data analysis with a lower risk of making a mistake.
• There is a 50/50 chance of being chosen.
• To complete the research, you’ll need less knowledge.
• It’s the most basic type of data collection.
• Forming sample groups is easier.
• The findings are applicable to the entire population.

Random Sampling’s disadvantages

Random Sampling’s disadvantages are given below:

• No extra information is taken into account.
• It is a time-consuming and complicated study method.
• Researchers need a lot of experience and a lot of talent.
• The excessively large sample size is likewise troublesome.
• To be effective, population grouping is required.
• There is a monetary expense associated with the procedure.
• There is no guarantee that the results will be universal.
• It’s just as easy to get the data wrong as it is to get it correctly.
• The utilization of large sample size is required.
• The quality of the data is determined by the researcher’s ability.

Conclusion

A simple random sample is a subset of individuals (a sample) selected at random from a larger group (a population) with the same probability. In srs, each subset of k people has the same chance of being chosen for the sample as every other subset of k people. An unbiased sampling strategy is a simple random sample.

Random sampling ensures that the findings you get from your sample are close to what you did get if you measured the complete population.