Find out how to display data using box and whisker plots, stem and leaf diagrams or histograms, and how to summarise data with measures of central location (mean, median, mode and quartiles) or measures of dispersion (range, interquartile range, variance and standard deviation), together with ideas of outliers and skewness. Use your graphic display calculator (GDC) to help speed up the calculations. See the Statistics diagrams page for a summary of the common diagrams used and use the Calculations page to practise using your calculator to find the summary statistics.