Sampling Error Definition, Example, Formula

In Statistics, sampling error also called estimation error is the amount of inaccuracy in estimating some value that is caused by only a portion of a population (i.e. sample) rather than the whole population. It is the difference between the statistic (value of the sample, such as sample mean) and the corresponding parameter (value of population, such as population mean) is called the sampling error. If $\bar{x}$ is the sample statistic and $\mu$ is the corresponding population parameter then it is defined as \[\bar{x} – \mu\].

Exact calculation/ measurements of sampling error are not feasible generally as the true value of the population is unknown usually, however, it can often be estimated by probabilistic modeling of the sample.

Sampling Error

Causes of Sampling-Error

  • The cause of the Error discussed may be due to the biased sampling procedure. Every research should select sample(s) that is free from any bias and the sample(s) are representative of the entire population of interest.
  • Another cause of this Error is chance. The process of randomization and probability sampling is done to minimize the sampling process error but it is still possible that all the randomized subjects/ objects are not representative of the population.

Eliminate/ Reduce the Sampling Error

The elimination/ Reduction of sampling-error can be done when a proper and unbiased probability sampling technique is used by the researcher and the sample size is large enough.

  • Increasing the sample size
    The sampling-error can be reduced by increasing the sample size. If the sample size $n$ is equal to the population size $N$, then the sampling error will be zero.
  • Improving the sample design i.e. By using the stratification
    The population is divided into different groups containing similar units.

The potential Sources of Errors are:

Potential Sources of Sampling and Non-Sampling

Also Read: Sampling and Non-Sampling Errors

Read more about Sampling Error on Wikipedia

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