Deviation from the true value that occurs due to chance alone. In general, the smaller the sample size, the larger the random error.

Deviation from the true value that occurs due to chance alone. In general, the smaller the sample size, the larger the random error.

The degree to which the sample is representative of the target population. It is required to extrapolate findings from the sampled population to the target population. It is sometimes referred to as ‘generalisability’.