Chapter 2: Graphs, Charts, and Tables--Describing Your Data

More documents

Recommendations

Info

76 CHAPTER 2 • GRAPHS, CHARTS, AND TABLES—DESCRIBING YOUR DATA 7FIGURE 2.21 Excel 2007 Output of Scatter Diagrams for Computers Data Excel 2007 Instructions: 1. Open file: Personal Computer.xls. 2. Select data for chart (Processor GHz and Price). 3. On Insert tab, click XY (Scatter), and then click Scatter with only Markers option. 4. Use the Layout tab of the Chart Tools to add titles and remove grid lines. 5. Use the Design tab of the Chart Tools to move the chart to a new worksheet. Minitab Instructions (for similar result): 1. Open file: Personal Computers.MTW. 2. Choose Graph > Scatterplot. 3. Select Simple. 4. Click OK. 5. In Y, enter Price column. In X, enter Processor Speed column. 6. Click OK. SUMMARY Constructing Scatter Diagrams A scatter diagram is a two-dimensional graph showing the joint values for two quantitative variables. It is constructed using the following steps: 1. Identify the two quantitative variables and collect paired responses for the two variables. 2. Determine which variable will be placed on the vertical axis and which variable will be placed on the horizontal axis. Often the vertical axis can be considered the dependent variable (y) and the horizontal axis can be considered the independent variable (x). 3. Define the range of values for each variable and define the appropriate scale for the x and y axes. 4. Plot the joint values for the two variables by placing a point in the x,y space. Do not connect the points. EXAMPLE 2-11 Scatter Diagrams TRY PROBLEM 2.47 Fortune’s Best Eight Companies Each year, Fortune magazine surveys employees regarding job satisfaction to try to determine which companies are the “best” companies to work for in the United States. Fortune also collects a variety of data associated with these companies. For example, the table here shows data for the top eight companies on
CHAPTER 2 • GRAPHS, CHARTS, AND TABLES—DESCRIBING YOUR DATA 77 three variables: number of U.S. employees; number of training hours per year per employee; and total revenue in millions of dollars. Company U.S. Employees Training Hr/Yr Revenues Southwest Airlines 24,757 15 $3,400 Kingston Technology 552 100 $1,300 SAS Institute 3,154 32 $653 Fel-Pro 2,577 60 $450 TD Industries 976 40 $127 MBNA 18,050 48 $3,300 W.L. Gore 4,118 27 $1,200 Microsoft 14,936 8 $8,700 To better understand these companies, we might be interested in the relationship between number of U.S. employees and revenue and between training hours and U.S. employees. To construct these scatter diagrams, we can use the following steps: Step 1 Identify the two variables of interest. In the first case, one variable is U.S. employees and the second is revenue. In the second case, one variable is training hours and the other is U.S. employees. Step 2 Identify the dependent and independent variables. In each case, think of U.S. employees as the independent (x) variable. Thus, Case 1: y revenue (vertical axis) Case 2: y training hours (vertical axis) x U.S. employees (horizontal axis) x U.S. employees (horizontal axis) Step 3 Establish the scales for the vertical and horizontal axes. The maximum value for each variable is revenue $8,700 U.S. employees 24,757 training hours 100 Step 4 Plot the joint values for the two variables by placing a point in the x, y space. $10,000 $9,000 Scatter Diagram Revenue (Millions) $8,000 $7,000 $6,000 $5,000 $4,000 $3,000 $2,000 $1,000 General Positive Relationship 0 0 5,000 10,000 15,000 U.S. Employees 20,000 25,000 30,000
Page 1 and 2: Chapter TWO Graphs, Charts, and Tab
Page 3 and 4: CHAPTER 2 • GRAPHS, CHARTS, AND T
Page 45: CHAPTER 2 • GRAPHS, CHARTS, AND T

Chapter 2: Graphs, Charts, and Tables--Describing Your Data

Create successful ePaper yourself

Delete template?

Save as template?