Box and whiskers power point

1. Warm Up
1. Order the test scores from least to
greatest: 89, 93, 79, 87, 91, 88, 92.
2. Find the median of the test scores.
Find the difference.
79, 87, 88, 89, 91, 92, 93
89
16.1
166.9
0.8
3.4
3. 17 – 0.9 4. 8.4 – 7. 6
5. 9.1 – 5.7 6. 190.3 – 23.4

2. Vocabulary
lower quartile
upper quartile
box-and-whisker plot
minimum
maximum

3. Litter Size 23456
Number of
Litters
168111
The table below summarizes a cat
breeder’s records for kitten litters born
in a given year. You can divide the data
into four equal part using quartiles.

4. Kitten Data
2 3 3 3 3 3 3 4 4 4 4 4 4 4 4 5 5 5 5 5 5 5 5 5 5 5 6
Lower half Upper half
Lower quartile: 3
median of lower half
Upper quartile: 5
median of upper half
Median: 4
You know that the median of a data set divides the
data into a lower half and an upper half. The median
of the lower half is the lower quartile, and the
median of the upper half is the upper quartile.

5. Find the lower and upper quartiles for the data
set.
Example 1: Finding Quartiles
A. 15, 83, 75, 12, 19, 74, 21
12 15 19 21 74 75 83 Order the values.
lower quartile: 15
upper quartile: 75

6. Find the lower and upper quartiles for the data
set.
Example 2: Finding Quartiles
B. 75, 61, 88, 79, 79, 99, 63, 77
61 63 75 77 79 79 88 99
lower quartile: = 69
63 + 75
2
upper quartile: = 83.5
79 + 88
2
Order the values.

7. Find the lower and upper quartiles for the data
set.
Check It Out! Example 3
A. 25, 38, 66, 19, 91, 47, 13
13 19 25 38 47 66 91 Order the values.
lower quartile: 19
upper quartile: 66

8. B. 45, 31, 59, 49, 49, 69, 33, 47
31 33 45 47 49 49 59 69 Order the values.
Find the lower and upper quartiles for the data
set.
Check It Out! Example 1
lower quartile: = 39
33 + 45
2
upper quartile: = 54
49 + 59
2

9. 1 2 3 4 5 6 7 8 9
A box-and-whisker plot shows the
distribution of data. The middle half of the
data is represented by a “box” with a vertical
line at the median. The lower fourth and
upper fourth quarters are represented by
“whiskers” that extend to the minimum
(least) and maximum (greatest) values.
Lower quartile Upper quartile
Median

10. Use the given data to make a box-and-whisker plot.
21, 25, 15, 13, 17, 19, 19, 21
Example 4: Making a Box-and-Whisker Plot
Step 1. Order the data from least to greatest. Then
find the minimum, lower quartile, median, upper
quartile, and maximum.
13 15 17 19 19 21 21 25
minimum: 13 maximum: 25
lower quartile: = 16
15 + 17
2
upper quartile: = 21
21 + 21
2
median: = 19
19 + 19
2

11. Use the given data to make a box-and-whisker plot.
12 14 16 18 20 22 24 26 28
Step 2. Draw a number line and plot a point above
each value from Step 1.
13 15 17 19 19 21 21 25
Example 4 Continued

12. Use the given data to make a box-and-whisker plot.
12 14 16 18 20 22 24 26 28
Step 3. Draw the box and whiskers.
13 15 17 19 19 21 21 25
Example 4 Continued

13. 23 24 26 29 31 31 33 35
Use the given data to make a box-and-whisker plot.
31, 23, 33, 35, 26, 24, 31, 29
Example 5
Step 1. Order the data from least to greatest. Then
find the minimum, lower quartile, median, upper
quartile, and maximum.
minimum: 23 maximum: 35
lower quartile: = 25
24 + 26
2
upper quartile: = 32
31 + 33
2
median: = 30
29 + 31
2

14. Use the given data to make a box-and-whisker plot.
22 24 26 28 30 32 34 36 38
Step 2. Draw a number line and plot a point above
each value.
23 24 26 29 31 31 33 35
Example 5 Continued

15. Step 2. Draw a number line and plot a point above
each value.
Use the given data to make a box-and-whisker plot.
22 24 26 28 30 32 34 36 38
Step 3. Draw the box and whiskers.
23 24 26 29 31 31 33 35
Example 5 Continued

16. Example 6
Quarter 1234
Oakland 30612
Tampa Bay 3171414
These box-and-whisker
plots compare the point
per quarter at Super
Bowl XXXVII.
Oakland
0 3 6 9 12 15 18
Tampa Bay
0 3 6 9 12 15 18

17. A. Compare the medians and ranges.
Example 6
The median for
Tampa Bay is
significantly
greater and the
range for Tampa
Bay is slightly
greater.
Oakland
0 3 6 9 12 15 18
Tampa Bay
0 3 6 9 12 15 18

18. B. Compare the ranges of the middle half of
the data for each.
Check It Out! Example 6
The range of
the middle half
of the data is
greater for
Tampa Bay.
Oakland
0 3 6 9 12 15 18
Tampa Bay
0 3 6 9 12 15 18

19. Lesson Quiz: Part I
Find the lower and upper quartiles for each
data set.
1. 48, 52, 68, 32, 53, 47, 51
2. 3, 18, 11, 2, 7, 5, 9, 6, 13, 1, 17, 8, 0
lower = 2.5; upper = 12
lower = 47; upper = 53

20. Lesson Quiz: Part II
Use the following data for problems 3 and 4.
91, 87, 98, 93, 89, 78, 94

3. Make a box-and-whisker plot.
4. What is the median and range of the data?
91; 20
78 87 91 94 98