WHAT IS SIMPLE RANDOM SAMPLING?
In research, it’s rarely possible (or practical) to collect data from every single person or item in a population. Instead, researchers collect information from a sample — a smaller group that represents the larger population.
Sampling saves time, cost, and effort, while still allowing researchers to make valid conclusions. However, how you select that sample matters — because if your sample is biased or unrepresentative, your results may be misleading.
One of the most widely used — and easiest to understand — sampling methods is Simple Random Sampling (SRS). Let’s break it down so that even if you’re new to research, you’ll feel confident about what it is and how to use it.
Definition of Simple Random Sampling
Simple Random Sampling is a method of selecting a sample where every individual in the population has an equal chance of being chosen.
Think of it like a lottery draw — each ticket (or person) has exactly the same chance of winning (or being selected).
In other words, there is no bias in who gets picked, and the selection is purely by chance.
Formula (Conceptual):
Probability of selection for each person = 1 / Total population size
If there are 100 people, each person has a 1/100 chance of being selected.
Key Characteristics of Simple Random Sampling
Here are the defining features that make a sample “simple random”:
- Equal Probability – Everyone in the population has the same chance of being chosen.
- Unbiased Selection – Selection is based on chance, not preference or judgment.
- Representativeness – If done correctly, the sample will reflect the diversity and characteristics of the whole population.
- Complete Sampling Frame – You need a full list of the population before you start.
Mini Checklist:
Step-by-Step Process
There are two main ways to conduct Simple Random Sampling — manual and software-based.
1. Manual Method
Best for small populations.
- List the entire population — Assign each member a number (e.g., from 1 to N).
- Decide the sample size — Example: You want to choose 10 people from 100.
- Use a random number method —
- Lottery method: Write numbers on slips of paper, mix them well, and draw at random.
- Random number table: Use a pre-generated table of random digits to pick numbers.
- Lottery method: Write numbers on slips of paper, mix them well, and draw at random.
2. Software-Based Method
Ideal for large populations or when you need speed.
- Prepare your population list — Each member should have a unique ID number.
- Use statistical tools or software — Examples:
- Microsoft Excel: Use =RAND() or =RANDBETWEEN() functions.
- SPSS, R, Python: Built-in random sampling functions.
- Microsoft Excel: Use =RAND() or =RANDBETWEEN() functions.
- Select the desired sample size — The software will pick at random.
Advantages of Simple Random Sampling
Why do researchers love this method?
- Fairness – Everyone has an equal shot at being chosen.
- Reduced Bias – Decisions are not influenced by personal preferences.
- Easy to Understand – Straightforward process that’s beginner-friendly.
- Statistical Validity – Works well with most statistical tests, making results more credible.
- High Representativeness – When the sample is large enough, it often mirrors the population’s characteristics.
Limitations of Simple Random Sampling
While it’s a great method, it’s not perfect:
- Need a Complete List – You must know every member of the population in advance.
- Not Always Practical – For huge populations, listing everyone is time-consuming.
- Cost and Time – Can be expensive or slow if the population is spread across wide areas.
- Risk of Unrepresentative Samples in Small Sizes – Chance alone can sometimes produce samples that don’t reflect the population well.
Practical Example
Scenario: You are researching the eating habits of university students at a campus with 2,000 students.
Step-by-Step:
- List all 2,000 students in a spreadsheet.
- Decide your sample size — say 200 students.
- Assign numbers from 1 to 2,000 to each student.
- Use Excel’s random number function to pick 200 unique numbers.
- The students match those numbers from your simple random sample.
In this way, each student — from the most outgoing to the quietest — has the same chance of being selected, ensuring fairness and minimizing bias.
Conclusion
Simple Random Sampling is like the “classic” of sampling methods — simple, fair, and reliable.
By giving everyone in the population an equal chance of being selected, it reduces bias and helps produce results you can trust. While it requires a complete list of your population and may not always be practical for huge groups, it remains one of the most important tools in a beginner researcher’s toolkit.
Key Takeaways:
- It’s random and unbiased.
- Works best when you have a complete population list.
- Easy to do manually for small groups or with software for large groups.
- Helps produce credible, representative results.
If you’re starting your research journey, mastering Simple Random Sampling is a small step that can make a big difference in the quality of your findings.