Box and Whisker Plots
Name: _________
A box and whisker plot is a visual way of displaying data.
Lower extreme: the smallest value in a set of data
Upper extreme: the biggest number in a set of data
Lower quartile: The median of the lower half of the data
Upper quartile: The median of the upper half of the data
The steps to creating a box and whisker plot are as follows:
1. Construct a number line and indicate the lower and upper extremes with dots.
2. Find the median. Mark this value on the number line using a vertical line.
3. Find the lower quartile. Mark this value on the number line using a vertical line.
4. Find the upper quartile. Mark this value on the number line using a vertical line.
5. Construct a box to show where the middle 50% of the data are located.
6. Extend a line from the box to the extremes to make the “whiskers”.
7. EXTRA: some box and whiskers also have a small square which represents the mean
Example 1
Data: 8, 38, 31, 12, 15, 30, 16, 28, 16, 18, 20, 27, 24, 24
Order your data:
Data: 8, 12, 15, 16, 16, 18, 20, 22, 24, 27, 28, 30, 31, 38
Lower Extreme: _____________
Upper Extreme: ____________
Median:
_____________
Example 2
Data:
9
12
13
14
15
Lower Extreme: _____________
Upper Extreme: ____________
Median:
_____________
Lower Quartile:
Upper Quartile:
15
16
18 20
Lower Quartile:
Upper Quartile:
TO TRY:
1. Make a box and whisker plot of the daily high temperatures in September in Muncie
43 81 48 60 56 45 52 49 60 68 85 74 77 84
Lower Extreme: _____________
Upper Extreme: ____________
Median:
_____________
Lower Quartile:
Upper Quartile:
2. Below are averages for car brand X gas mileage per mile for. To market the car you
must let them know what the possibilities are. To figure this out your boss has asked you
to arrange the averages into a box-and-whisker plot so that they know where most
consumers will fall when buying car brand X.
31 27 12 23 45 24 39 19 48 24 20 22 29 17 34
Lower Extreme: _____________
Upper Extreme: ____________
Median:
_____________
Lower Quartile:
Upper Quartile:
3. Ten flashlight batteries were purchased and were tested to determine how many hours
they would last. The results are listed below. Make a box and whisker plot of the data.
15 14 14 24 19 17 15 11 16 15
Lower Extreme: _____________
Upper Extreme: ____________
Median:
_____________
Lower Quartile:
Upper Quartile: