How do I creat a box and whisker plot?

Question

I know you have to create a box around the median of a data set of numbers, but I do not know where the end of the box would be placed. Please help!

Answer 1

Given your set of data, first you want to determine $Q_1,Q_2,Q_3$, the lower quartile, the median, and the upper quartile, respectively. The box goes from $Q_1$ to $Q_3$, which covers the interquartile range. It is possible that some points are to the left of $Q_1$ and to the right of $Q_3$. Depending on how far they are from the plot, we call these points (extreme) outliers.