Statistics for Managers using Microsoft Excel 3 rd Edition

Transcription

1 Statistics for Managers using Microsoft Excel 3 rd Edition Chapter 2 Presenting Data in Tables and Charts 22 Prentice-Hall, Inc. Chap 2-1

2 Chapter Topics Organizing numerical data The ordered array and stem-leaf display Tabulating and graphing Univariate numerical data Frequency distributions: tables, histograms, polygons Cumulative distributions: tables, the Ogive Graphing Bivariate numerical data 22 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 Tabulating and graphing Bivariate categorical data Contingency tables Side by side bar charts Graphical excellence and common errors in presenting data (continued) 22 Prentice-Hall, Inc. Chap 2-3

4 Organizing Numerical Data Numerical Data 41, 24, 32, 26, 27, 27, 3, 24, 38, 21 Ordered Array 21, 24, 24, 26, 27, 27, 3, 32, 38, 41 Frequency Distributions Cumulative Distributions Stem and Leaf Display Tables Histograms Polygons Ogive 22 Prentice-Hall, Inc. Chap 2-4

5 Organizing Numerical Data Data in raw form (as collected): 24, 26, 24, 21, 27, 27, 3, 41, 32, 38 Data in ordered array from smallest to largest: 21, 24, 24, 26, 27, 27, 3, 32, 38, 41 Stem-and-leaf display: (continued) 22 Prentice-Hall, Inc. Chap 2-5

6 Tabulating and Graphing Numerical Data Numerical Data 41, 24, 32, 26, 27, 27, 3, 24, 38, 21 Ordered Array 21, 24, 24, 26, 27, 27, 3, 32, 38, 41 Frequency Distributions Cumulative Distributions O give Stem and Leaf Display Histograms 7 6 Tables Ogive Polygons Prentice-Hall, Inc. Chap 2-6

7 Tabulating Numerical Data: Frequency Distributions Sort raw data in ascending order: 12, 13, 17, 21, 24, 24, 26, 27, 27, 3, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 Find range: = 46 Select number of classes: 5 (usually between 5 and 15) Compute class interval (width): 1 (46/5 then round up) Determine class boundaries (limits): 1, 2, 3, 4, 5, 6 Compute class midpoints: 15, 25, 35, 45, 55 Count observations & assign to classes 22 Prentice-Hall, Inc. Chap 2-7

8 Class Frequency Distributions, Relative Frequency Distributions and Percentage Distributions Data in ordered array: 12, 13, 17, 21, 24, 24, 26, 27, 27, 3, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 Frequency Relative Frequency Percentage 1 but under but under but under but under but under Total Prentice-Hall, Inc. Chap 2-8

9 Frequency Graphing Numerical Data: The Histogram Data in ordered array: 12, 13, 17, 21, 24, 24, 26, 27, 27, 3, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 Histogram More No Gaps Between Bars Class Boundaries Class Midpoints 22 Prentice-Hall, Inc. Chap 2-9

10 Graphing Numerical Data: The Frequency Polygon Data in ordered array: 12, 13, 17, 21, 24, 24, 26, 27, 27, 3, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 F r e q u e n c y M o r e Class Midpoints 22 Prentice-Hall, Inc. Chap 2-1

11 Tabulating Numerical Data: Cumulative Frequency Data in ordered array: 12, 13, 17, 21, 24, 24, 26, 27, 27, 3, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 Cumulative Cumulative Class Frequency % Frequency 1 but under but under but under but under but under Prentice-Hall, Inc. Chap 2-11

12 Graphing Numerical Data: The Ogive (Cumulative % Polygon) Data in ordered array: 12, 13, 17, 21, 24, 24, 26, 27, 27, 3, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 Ogive Class Boundaries (Not Midpoints) 22 Prentice-Hall, Inc. Chap 2-12

13 Total Year to Date Return (%) Graphing Bivariate Numerical Data (Scatter Plot) Mutual Funds Scatter Plot Net Asset Values 22 Prentice-Hall, Inc. Chap 2-13

14 Tabulating and Graphing Categorical Data:Univariate Data Categorical Data Tabulating Data The Summary Table Graphing Data Pie Charts Bar Charts Pareto Diagram 22 Prentice-Hall, Inc. Chap 2-14

15 Summary Table (for an Investor s Portfolio) Investment Category Amount Percentage (in thousands $) Stocks Bonds CD Savings Total 11 1 Variables are Categorical 22 Prentice-Hall, Inc. Chap 2-15

16 Graphing Categorical Data: Univariate Data Categorical Data Tabulating Data The Summary Table Graphing Data Pie Charts CD S a vin g s B o n d s Bar Charts Pareto Diagram S to c k s S t o c k s B o n d s S a vin g s CD 22 Prentice-Hall, Inc. Chap 2-16

17 Bar Chart (for an Investor s Portfolio) Investor's Portfolio Savings CD Bonds Stocks Amount in K$ 22 Prentice-Hall, Inc. Chap 2-17

18 Pie Chart (for an Investor s Portfolio) Amount Invested in K$ Savings 15% CD 14% Stocks 42% Bonds 29% Percentages are rounded to the nearest percent. 22 Prentice-Hall, Inc. Chap 2-18

19 Pareto Diagram 45% 1% 4% 9% Axis for bar chart shows % invested in each category 35% 3% 25% 2% 15% 1% 5% % Stocks Bonds Savings CD 8% 7% 6% 5% 4% 3% 2% 1% % Axis for line graph shows cumulative % invested 22 Prentice-Hall, Inc. Chap 2-19

20 Tabulating and Graphing Bivariate Categorical Data Contingency tables: investment in thousands of dollars Investment Investor A Investor B Investor C Total Category Stocks Bonds CD Savings Total Prentice-Hall, Inc. Chap 2-2

21 Tabulating and Graphing Bivariate Categorical Data Side by side charts C omparing Investors S avings CD B onds S toc k s Inves tor A Inves tor B Inves tor C 22 Prentice-Hall, Inc. 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 22 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 22 Prentice-Hall, Inc. Chap 2-23

24 Chart Junk Bad Presentation Good Presentation Minimum Wage 196: $1. 197: $ : $ : $ $ Minimum Wage Prentice-Hall, Inc. Chap 2-24

25 No Relative Basis 3 2 Bad Presentation Freq. A s received by students. FR SO JR SR 3 1 % Good Presentation A s received by students. FR SO JR SR FR = Freshmen, SO = Sophomore, JR = Junior, SR = Senior 22 Prentice-Hall, Inc. Chap 2-25

26 Compressing Vertical Axis 2 1 Bad Presentation $ Quarterly Sales 5 25 Good Presentation $ Quarterly Sales Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 22 Prentice-Hall, Inc. Chap 2-26

27 No Zero Point on Vertical Axis $ Bad Presentation Monthly Sales J F M A M J Good Presentation $ Monthly Sales J F M A M J Graphing the first six months of sales. 22 Prentice-Hall, Inc. Chap 2-27

28 Chapter Summary Organized numerical data The ordered array and stem-leaf display Tabulated and graphed univariate numerical data Frequency distributions: tables, histograms, polygon Cumulative distributions: tables and the Ogive Graphed bivariate numerical data 22 Prentice-Hall, Inc. Chap 2-28

29 Chapter Summary (continued) Tabulated and graphed univariate categorical data The summary table Bar and pie charts, the Pareto diagram Tabulated and graphed bivariate categorical data Contingency tables Side by side charts Discussed graphical excellence and common errors in presenting data 22 Prentice-Hall, Inc. Chap 2-29