‘Simple descriptions’ outlines the basic tools available to statisticians. Data describe the universe we wish to study, but it can never be an exhaustive description of our subject. It is common to convert our data into numerical values, as these values have only one property, and as such can be easily compared and manipulated. Simple summary statistics allow us to condense relationships between a distribution of data to a single value. Averaging is a common summary statistic, and can be expressed as the mean, median, or mode. The dispersion of data is also important, and can be measured by the range, standard deviation, skewness and quantiles.