This slide is about stem and leaf display

1. Slide 1
Exploratory Data Analysis
 We have techniques used to summarize data quickly.
 One such technique is the stem-and-leaf display.
Data: 21, 24, 24, 26, 27, 27, 30, 32, 38, 41
2 144677
3 028
4 1

2.  A stem-and-leaf display shows both the rank order
and shape of the distribution of the data.
 It is similar to a histogram on its side, but it has the
advantage of showing the actual data values.
 The first digits of each data item are arranged to the
left of a vertical line.
digit for each item in rank order--when the leaf unit is
not shown, it is assumed to equal 1.
Slide 2
Stem-and-Leaf Display
 To the right of the vertical line we record the next
 Each line in the display is referred to as a stem.
 Each digit on a stem is a leaf.

3. Slide 3
Example: Hudson Auto Repair
The manager of Hudson Auto
would like to have a better
understanding of the cost
of parts used in the engine
tune-ups performed in the
shop. She examines 50
customer invoices for tune-ups. The costs of parts,
rounded to the nearest dollar, are listed on the next
slide.

4. Slide 4
Example: Hudson Auto Repair
 Sample of Parts Cost for 50 Tune-ups
91 78 93 57 75 52 99 80 97 62
71 69 72 89 66 75 79 75 72 76
104 74 62 68 97 105 77 65 80 109
85 97 88 68 83 68 71 69 67 74
62 82 98 101 79 105 79 69 62 73
First step is to rearrange these data
in rank order. See next slide.

5. Slide 5
Solution: Stem-and-Leaf Display
5
6
7
8
9
10
2 7
2 2 2 2 5 6 7 8 8 8 9 9 9
1 1 2 2 3 4 4 5 5 5 6 7 8 9 9 9
0 0 2 3 5 8 9
1 3 7 7 7 8 9
1 4 5 5 9
a stem
a leaf
So What?
Explain!
•When the leaf unit is not shown,
it is assumed to equal 1.

6. Slide 6
Solution: Hudson Auto Repair
 Sample of Parts Cost for 50 Tune-ups
52 57 62 62 62 62 65 66 67 68 68 68 69 69 69
71 71 72 72 73 74 74 75 75 75 76 77 78 79
79 79 80 80 82 83 85 88 89 91 93 97 97 97
98 99 101 104 105 105 109
Data are rearranged in rank order.

7. Slide 7
Tabular and Graphical Procedures
Qualitative Data Quantitative Data
Tabular
Methods
Tabular
Methods
Graphical
Methods
Graphical
Methods
•Frequency
Distribution
•Rel. Freq. Dist.
•Percent Freq.
Distribution
•Bar Graph
•Pie Chart
•Frequency
Distribution
•Rel. Freq. Dist.
•Cum. Freq. Dist.
•Cum. Rel. Freq.
Distribution
•Stem-and-Leaf
Display
•Crosstabulation
(Contingency
Table)
•Dot Plot
•Histogram
•Scatter
Diagram
Data