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One important statistical display is a box plot. If you need help remembering what a box plot is, refer to the glossary in the eBook before you complete parts (a) through (d) below.  

  1. What is the median shoe size in problem 1‑30? The minimum shoe size? The maximum?

    The median is the middle value when all values are arranged from least (minimum) to greatest (maximum).

  2. What are the quartiles (the median of the upper half, and the median of the lower half)?

    To find the quartiles, divide the data into two portions, one made up of the values larger than the median, and the other made up of the values smaller than the median.

    Find the median of each data set. Since each will be composed of an even number of values, find the mean (average) of the two middle values.

  3. Above a number line, plot the five numbers you found in parts (a) and (b) and then create a box plot.

    In a box plot, the maximum, minimum, median, and upper and lower quartiles are marked with short vertical line segments. Connect the line segments for the quartiles to form the box. Connect the line segments for the maximum and minimum to the box with horizontal line segments.

  4. Where does your own shoe size fall in the distribution of Kerin’s classmates?

    In which quartile does your shoe size fall? Is your shoe size smaller than the minimum or larger than the maximum?

Use the eTool below to create a box plot.
Click the link at right for the full version of the eTool: 1-31 HW eTool