Chapters: 1: Introduction 2: Simple example 3: Invocation 4: Finer Control 5: X-Y Plots 6: Contour Plots 7: Image Plots 8: Examples 9: Gri Commands 10: Programming 11: Environment 12: Emacs Mode 13: History 14: Installation 15: Gri Bugs 16: Test Suite 17: Gri in Press 18: Acknowledgments 19: License Indices: Concepts Commands Variables | ## 8.1: Box plots Box plots were invented by Tukey for eda (exploratory data analysis). They show nonparametric statistics. The centre of the box is the median. The box edges show the first quartile (q1) and the third quartile (q3). The distance from q3 to q1 is called the inter-quartile range. The whiskers (lines with crosses on them) extend to the furthest points still within 1.5 inter-quartile ranges of q1 and q3. Beyond the whiskers, all outliers are shown, in open circles up to a distance of 3 inter-quartile ranges beyond q1 and q3, and in closed circles beyond that. Below is an example that uses a "new command" to define each box plot (see Adding New Commands). The command-file.