STT 212 Lecture Notes - Lecture 2: Box Plot, Interquartile Range, Quartile
Document Summary
To construct a box plot, use a horizontal or vertical number line and a rectangular box. The smallest and largest data values label the endpoints of the axis. The first quartile marks one end of the box and the third quartile marks the other end of the box. Approximately the middle 50 percent of the data fall inside the box . The whiskers extend from the ends of the box to the smallest and largest data values. The median or second quartile can be between the first and third quartiles, or it can be one, or the other, or both. The box plot gives a good, quick picture of the data. The following data are the heights of 40 students in a statistics class. Construct a box plot with the following properties; the calculator instructions for the minimum and maximum values as well as the quartiles follow the example. Each quarter has approximately 25% of the data.