Measures of variability are vital in biostatistics for describing a dataset's dispersions and highlighting deviations between individual data points.

The range is the difference between the highest and lowest values in a dataset.

Confidence intervals provide a range within which a true population parameter likely falls. For example, a 95% confidence interval for mean blood pressure offers a likely range for the actual population mean.

The standard deviation represents the average distance between each data point and the mean, while the variance equals the squared value of the standard deviation.

Both standard deviation and variance can help compare data between different treatment groups in a clinical trial.

Lastly, the coefficient of variation, expressed as a percentage, compares the standard deviation to the mean, providing a measure of relative variability.

It helps compare the variability of two different datasets with different means, like blood glucose levels in various diabetic patient groups.