In a box and whisker plot: the ends of the box are the upper and lower quartiles, so the box spans the interquartile range; the median is marked by a vertical line inside the box; the whiskers are the two lines outside the box that extend to the highest and lowest observations. Example 1 â Box and whisker plots Summary A box and whisker plot (sometimes called a boxplot) is a graph that presents information from a five-number summary. It does not show a distribution in as much detail as a stem and leaf plot or histogram does, but is especially useful for indicating whether a distribution is skewed and whether there are potential unusual observations in the data set.
Causes and Risk Factors for Henoch-Schonlein Purpura. The exact cause of HSP is not known. The body's immune system is believed to play a role in targeting the blood vessels involved. An abnormal immune response to an infection may be a factor in many cases.
1 HBP causes artery damage, and the kidneys are packed with arteries. 2  Kidneys are supplied with dense blood vessels, and high volumes of blood flow through them. 3  Over time, uncontrolled high blood pressure can cause arteries around the kidneys to narrow, weaken or harden.