Transcript Box & Whisker & Dot Plots

Box-and-whisker plots & Dot
Plots
How to read a box-and-whisker plot.
• Dots outside of the box
and whiskers are outliers.
• Maximum and minimum
values are shown at the
ends of each whisker.
• The upper and lower
quartiles are the ends of
the box.
• The median is the line in
the middle of the box.
Outlier
Minimum
Lower
quartile
Median
Upper
quartile
Maximum
Outlier
Example 1
• Ruby asked the students in her class how long
their families spent making dinner each night.
This box-and-whisker plot shows the results.
Find the following values:
Minimum: 20
LQ: 25 Maximum: 50 UQ: 45
Range: 30
Interquartile Range: 20 Median: 35
Practice Problem 1
• A professor asked her students to keep track
of how many websites they visit each day. This
box-and-whisker plot shows the results.
Find the following values:
Minimum: 4
LQ: 5 Maximum:
Range: 6
Interquartile Range: 3
10
UQ: 8
Median:
7
How to read dot plots
• The dots above each number represent a
number in the data set.
• If dots are stacked on top of each other, that
means that the value occurs more than once.
• Labeling the axis is key to determining the
numbers in the data set.
Example 2
• From the dot plot below, you can see that there
are few values near the maximum and minimum
values.
• There are clusters of values between 64 and 80.
• You can infer that for this dot plot, most people’s
pulses were between 64bpm and 80 bpm.
Comparing two dot plots
• The dotplots to the right show
pet ownership in two city
blocks.
• As seen in the graph, pet
ownership in block a is lower.
– In block a, the amount of pets that
people own ranges between 0 and 4.
• In block b, most households
have two or more pets.
– In block b, the amount of pet ranges
between 0 and 6.
Practice Problem
• The dot plot below shows the age of actors
and actresses who win awards. Make a
prediction about the ages of actresses and
actors in the dot plots below.
Actresses win more awards than actors at a younger age.
Actors win more awards than actresses at an older age.