What is Variable Sampling?

Variable sampling is a statistical method used in quality assurance and control processes. In variable sampling, you measure the results on a continuous scale, while in attribute sampling, the results are binary (e.g., fit/unfit, pass/fail, etc.).

Variable sampling helps determine the population’s mean, variance, etc., based on a given sample. Using this sampling, you can analyze the entire population from the sample.

Statistical sampling provides better estimates than attribute sampling, as it provides results on a continuous scale, which is impossible with attribute sampling. It provides a range of values, thus resulting in a more detailed analysis.

The only drawback of this technique is that it requires more effort to carry out this statistical sampling and analyze the results.

Examples of Variable Sampling

Now, we will see a few examples of variable sampling in different industries:

Quality Control

• Manufacturing: The manufacturing industry measures the weight of individual products and uses the sample mean to estimate the average weight of the entire batch.
• Pharmaceuticals: The pharmaceutical industry tests the potency of different medicine batches by measuring the active ingredient concentration in samples from each batch.

Research

• Economics: The economics industry surveys a sample of households to estimate the average income in a city.
• Healthcare: During clinical trials, the healthcare industry regularly collects blood samples from patients to measure the concentration of a drug in their bloodstream.

Engineering

• Civil Engineering: The civil engineering industry measures the strength of individual concrete samples to estimate the overall strength of a bridge.
• Software Engineering: The software engineering industry measures the response time of a website on different servers to identify performance bottlenecks.

How Does Variable Sampling Work?

First, you will define your objective, e.g., what data you will need to collect and the sample size. Afterward, you will collect the sample size as defined initially.

You will calculate the different parameters, such as mean and variance, and further analyze the data. Finally, you will conclude the whole population and make the decisions.

Conclusion

Variable sampling provides a robust approach to quality management, which allows you to evaluate quantitative attributes precisely and accurately. You can identify standard deviations, implement corrective actions, and continuously improve your products and services.