Statistics for Managers using Microsoft Excel 3rd Edition

1. Statistics for Managers using Microsoft Excel 3rd Edition

Chapter 2
Presenting Data in
Tables and Charts
© 2002 Prentice-Hall, Inc.
Chap 2-1

2. Chapter Topics

Organizing numerical data
Tabulating and graphing Univariate numerical
data
The ordered array and stem-leaf display
Frequency distributions: tables, histograms,
polygons
Cumulative distributions: tables, the Ogive
Graphing Bivariate numerical data
© 2002 Prentice-Hall, Inc.
Chap 2-2

3. Chapter Topics

Tabulating and graphing Univariate
categorical data
The summary table
Bar and pie charts, the Pareto diagram
(continued)
Tabulating and graphing Bivariate categorical
data
Contingency tables
Side by side bar charts
Graphical excellence and common errors in
presenting data
© 2002 Prentice-Hall, Inc.
Chap 2-3

4. Organizing Numerical Data

Numerical Data
Ordered Array
21, 24, 24, 26, 27, 27, 30, 32, 38, 41
Stem and Leaf
Display
© 2002 Prentice-Hall, Inc.
2 144677
3 028
4 1
41, 24, 32, 26, 27, 27, 30, 24, 38, 21
Frequency Distributions
Cumulative Distributions
Histograms
Tables
Ogive
Polygons
Chap 2-4

5. Organizing Numerical Data

(continued)
Data in raw form (as collected):
24, 26, 24, 21, 27, 27, 30, 41, 32, 38
Data in ordered array from smallest to largest:
21, 24, 24, 26, 27, 27, 30, 32, 38, 41
Stem-and-leaf display:
2 144677
3 028
4 1
© 2002 Prentice-Hall, Inc.
Chap 2-5

6. Tabulating and Graphing Numerical Data

Numerical Data
Ordered Array
21, 24, 24, 26, 27, 27, 30, 32, 38, 41
41, 24, 32, 26, 27, 27, 30, 24, 38, 21
Frequency Distributions
Cumulative Distributions
O g ive
120
100
80
60
40
20
0
10
Stem and Leaf
Display
2 144677
3 028
4 1
Histograms
30
40
50
60
Ogive
7
6
5
4
Tables
Polygons
3
2
1
0
10
© 2002 Prentice-Hall, Inc.
20
20
30
40
50
60
Chap 2-6

7. Tabulating Numerical Data: Frequency Distributions

Sort raw data in ascending order:
12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58
Find range: 58 - 12 = 46
Select number of classes: 5 (usually between 5 and 15)
Compute class interval (width): 10 (46/5 then round up)
Determine class boundaries (limits):
Compute class midpoints:
Count observations & assign to classes
© 2002 Prentice-Hall, Inc.
10, 20, 30, 40, 50, 60
15, 25, 35, 45, 55
Chap 2-7

8. Frequency Distributions, Relative Frequency Distributions and Percentage Distributions

Data in ordered array:
12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58
Class
10 but under 20
20 but under 30
30 but under 40
40 but under 50
50 but under 60
Total
© 2002 Prentice-Hall, Inc.
Relative
Frequency Frequency Percentage
3
6
5
4
2
20
.15
.30
.25
.20
.10
1
15
30
25
20
10
100
Chap 2-8

9. Graphing Numerical Data: The Histogram

Data in ordered array:
12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58
Frequency
Histogram
7
6
5
4
3
2
1
0
6
5
3
2
0
5
Class Boundaries
© 2002 Prentice-Hall, Inc.
No Gaps
Between
Bars
4
0
15
25
36
45
Class Midpoints
55
More
Chap 2-9

10. Graphing Numerical Data: The Frequency Polygon

Data in ordered array:
12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58
Fre q u e n c y
7
6
5
4
3
2
1
0
5
© 2002 Prentice-Hall, Inc.
15
25
36
45
55
Class Midpoints
M o re
Chap 2-10

11. Tabulating Numerical Data: Cumulative Frequency

Data in ordered array:
12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58
Class
10 but under 20
20 but under 30
30 but under 40
40 but under 50
50 but under 60
© 2002 Prentice-Hall, Inc.
Cumulative
Frequency
3
9
14
18
20
Cumulative
% Frequency
15
45
70
90
100
Chap 2-11

12. Graphing Numerical Data: The Ogive (Cumulative % Polygon)

Data in ordered array:
12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58
Ogive
100
80
60
40
20
0
10
20
30
40
50
60
Class Boundaries (Not Midpoints)
© 2002 Prentice-Hall, Inc.
Chap 2-12

13. Graphing Bivariate Numerical Data (Scatter Plot)

Mutual Funds Scatter Plot
Total Year to
Date Return
(%)
40
30
20
10
0
0
© 2002 Prentice-Hall, Inc.
10
20
30
Net Asset Values
40
Chap 2-13

14. Tabulating and Graphing Categorical Data:Univariate Data

Categorical Data
Tabulating Data
The Summary Table
Graphing Data
Pie Charts
Bar Charts
© 2002 Prentice-Hall, Inc.
Pareto Diagram
Chap 2-14

15. Summary Table (for an Investor’s Portfolio)

Investment Category
Amount
Percentage
(in thousands $)
Stocks
Bonds
CD
Savings
Total
46.5
32
15.5
16
110
42.27
29.09
14.09
14.55
100
Variables are Categorical
© 2002 Prentice-Hall, Inc.
Chap 2-15

16. Graphing Categorical Data: Univariate Data

Categorical Data
Graphing Data
Tabulating Data
The Summary Table
Pie Charts
CD
Pareto Diagram
S a vi n g s
Bar Charts
B onds
S to c k s
0
10
20
30
40
50
45
120
40
100
35
30
80
25
60
20
15
40
10
20
5
0
0
S to c k s
© 2002 Prentice-Hall, Inc.
B onds
S a vi n g s
CD
Chap 2-16

17. Bar Chart (for an Investor’s Portfolio)

Investor's Portfolio
Savings
CD
Bonds
Stocks
0
10
20
30
40
50
Amount in K$
© 2002 Prentice-Hall, Inc.
Chap 2-17

18. Pie Chart (for an Investor’s Portfolio)

Amount Invested in K$
Savings
15%
Stocks
42%
CD
14%
Bonds
29%
© 2002 Prentice-Hall, Inc.
Percentages are
rounded to the
nearest percent.
Chap 2-18

19. Pareto Diagram

Axis for
bar
chart
shows
%
invested
in each
category
45%
100%
40%
90%
80%
35%
70%
30%
60%
25%
50%
20%
40%
15%
30%
10%
20%
5%
10%
0%
0%
Stocks
© 2002 Prentice-Hall, Inc.
Bonds
Savings
Axis for line
graph
shows
cumulative
% invested
CD
Chap 2-19

20. Tabulating and Graphing Bivariate Categorical Data

Contingency tables:
Investment
Category
Investor A
Stocks
Bonds
CD
Savings
46.5
32
15.5
16
Total
110
© 2002 Prentice-Hall, Inc.
investment in thousands of dollars
Investor B
Investor C
Total
55
44
20
28
27.5
19
13.5
7
129
95
49
51
147
67
324
Chap 2-20

21. Tabulating and Graphing Bivariate Categorical Data

Side by side charts
C o m p arin g In vesto rs
S avings
CD
B onds
S toc k s
0
10
Inves tor A
© 2002 Prentice-Hall, Inc.
20
30
Inves tor B
40
50
60
Inves tor C
Chap 2-21

22. Principles of Graphical Excellence

Presents data in a way that provides
substance, statistics and design
Communicates complex ideas with clarity,
precision and efficiency
Gives the largest number of ideas in the most
efficient manner
Almost always involves several dimensions
Tells the truth about the data
© 2002 Prentice-Hall, Inc.
Chap 2-22

23. Errors in Presenting Data

Using “chart junk”
Failing to provide a relative
basis in comparing data
between groups
Compressing the vertical axis
Providing no zero point on the vertical axis
© 2002 Prentice-Hall, Inc.
Chap 2-23

24. “Chart Junk”

Bad Presentation
Good Presentation
Minimum Wage
1960: $1.00
Minimum Wage
4
$
1970: $1.60
2
1980: $3.10
0
1990: $3.80
© 2002 Prentice-Hall, Inc.
1960
1970
1980
1990
Chap 2-24

25. No Relative Basis

Bad Presentation
Good Presentation
A’s received by
Freq. students.
300
200
30 %
10
0
FR SO
JR SR
A’s received by
students.
FR SO JR SR
FR = Freshmen, SO = Sophomore, JR = Junior, SR = Senior
© 2002 Prentice-Hall, Inc.
Chap 2-25

26. Compressing Vertical Axis

Bad Presentation
Good Presentation
Quarterly Sales
200
$
Quarterly Sales
50
100
25
0
0
Q1 Q2
© 2002 Prentice-Hall, Inc.
Q3 Q4
$
Q1
Q2
Q3 Q4
Chap 2-26

27. No Zero Point on Vertical Axis

Bad Presentation
Good Presentation
Monthly Sales
45
$
Monthly Sales
42
39
45
42
39
$
36
36
J F M A M J
0
J F M A M J
Graphing the first six months of sales.
© 2002 Prentice-Hall, Inc.
Chap 2-27

28. Chapter Summary

Organized numerical data
Tabulated and graphed univariate numerical
data
The ordered array and stem-leaf display
Frequency distributions: tables, histograms,
polygon
Cumulative distributions: tables and the Ogive
Graphed bivariate numerical data
© 2002 Prentice-Hall, Inc.
Chap 2-28

29. Chapter Summary

Tabulated and graphed univariate categorical
data
The summary table
Bar and pie charts, the Pareto diagram
Tabulated and graphed bivariate categorical
data
(continued)
Contingency tables
Side by side charts
Discussed graphical excellence and common
errors in presenting data
© 2002 Prentice-Hall, Inc.
Chap 2-29