So our tallest normal tree is a whopping 110 inches. The line at the furthest right represents the highest value in the data. In the case of our trees, the smallest is about 30 inches tall. The line at the furthest left represents the lowest value in the data. We’ll talk about how really useful this box is in just a minute. It represents 50% of data points between the 1st and 3rd quartiles. Hence the reason I supplemented the data. Just so you know, in a typical data set without supplemented data, you may not see that little dot because it should be close to the median value. Remember from long, long ago in a post far, far away that the mean is actually a statistical model that represents the data. The mean value of the data may not always be an actual value in the data. The dot beside the line, but still inside the yellow box represents the mean value of the data. On the graph, the vertical line inside the yellow box represents the median value of the data set. The Basics of the Boxplotįirst, let’s look at a boxplot using some data on dogwood trees that I found and supplemented. It also shows a few other pieces of data. Recall that the measures of central tendency include the mean, median, and mode of the data. One wicked awesome thing about box plots is that they contain every measure of central tendency in a neat little package. By John Clark on Januin Descriptive Statisticsīox plots, or box-and-whisker plots, are fantastic little graphs that give you a lot of statistical information in a cute little square.