Random samples

The mechanism of sampling from a population explains randomness in data.

Variability of sample statistics

The randomness of samples also results in randomness of summary statistics from these samples.

The remainder of this section investigates the variability in sample means.

Tread depth of taxi tyres

We now demonstrate the sample-to-sample variability of sample means and standard deviations when sampling from a finite population.

The mean from a single sample provides a reasonable estimate of the population mean but the sample-to-sample variability affects its accuracy.