Box

1
Box and Whisker Plots
A Box and Whisker Diagram or a Box Plot is a
graph drawn using the

• Median
• Upper and Lower Quartile
• Interquartile range.

A Box Plot looks like this
Lower Quartile The Median of the bottom half of
the scores
Upper Quartile The Median of the upper half of
the scores
NOTE each part is not necessarily the same size,
in depends on your scores.
2
Box and Whisker Plots
Each of the sets of figures below (in rows) have
the same Box and Whisker Plot. This plot is shown
below.
Transfer these figures to the student
calculators, and get them to use the HP Box and
Whisker Plot to demonstrate this
3
Box and Whisker Plots
Outliers Scores more than 1.5 times greater than
the IQR (Interquartile Range) are called
Outliers. At this point the whiskers stop. Find
the cut-offs Outliers for Qs 1 to 4, 6 to 9
Q 14