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Lecture Statistical techniques in business and economics (14/e): Chapter 2 - Lind, Marchal, Wathen

Chapter 2 - Describing data: Frequency tables, frequency distributions, and graphic presentation. When you have completed this chapter, you will be able to: Organize qualitative data into a frequency table, present a frequency table as a bar chart or a pie chart, organize quantitative data into a frequency distribution, present a frequency distribution for quantitative data using histograms, frequency polygons, and cumulative frequency polygons. | Chapter 2 Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation McGraw-Hill/Irwin Copyright © 2010 by The McGraw-Hill Companies, Inc. All rights reserved. GOALS Organize qualitative data into a frequency table. Present a frequency table as a bar chart or a pie chart. Organize quantitative data into a frequency distribution. Present a frequency distribution for quantitative data using histograms, frequency polygons, and cumulative frequency polygons. Frequency Table and Frequency Distribution FREQUENCY TABLE A grouping of qualitative data into mutually exclusive classes showing the number of observations in each class. FREQUENCY DISTRIBUTION A grouping of data into mutually exclusive classes showing the number of observations in each class. Class interval: The class interval is obtained by subtracting the lower limit of a class from the lower limit of the next class. Class frequency: The number of observations in each class. Class midpoint: A . | Chapter 2 Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation McGraw-Hill/Irwin Copyright © 2010 by The McGraw-Hill Companies, Inc. All rights reserved. GOALS Organize qualitative data into a frequency table. Present a frequency table as a bar chart or a pie chart. Organize quantitative data into a frequency distribution. Present a frequency distribution for quantitative data using histograms, frequency polygons, and cumulative frequency polygons. Frequency Table and Frequency Distribution FREQUENCY TABLE A grouping of qualitative data into mutually exclusive classes showing the number of observations in each class. FREQUENCY DISTRIBUTION A grouping of data into mutually exclusive classes showing the number of observations in each class. Class interval: The class interval is obtained by subtracting the lower limit of a class from the lower limit of the next class. Class frequency: The number of observations in each class. Class midpoint: A point that divides a class into two equal parts. This is the average of the upper and lower class limits. Pie Charts and Bar Charts PIE CHART A chart that shows the proportion or percent that each class represents of the total number of frequencies. BAR CHART A graph in which the classes are reported on the horizontal axis and the class frequencies on the vertical axis. The class frequencies are proportional to the heights of the bars. Relative Class Frequencies Class frequencies can be converted to relative class frequencies to show the fraction of the total number of observations in each class. A relative frequency captures the relationship between a class total and the total number of observations. EXAMPLE – Creating a Frequency Distribution Table Ms. Kathryn Ball of AutoUSA wants to develop tables, charts, and graphs to show the typical selling price on various dealer lots. The table on the right reports only the price of the 80 vehicles sold last month at Whitner Autoplex.