1、 2-1Business StatisticsChapter 2Organizing and Visualizing Variables2-2Chapter GoalsAfter completing this chapter, you should be able to: n Create an ordered array and a stem-and-leaf displayn Construct and interpret a frequency distribution, polygon, and Ogive n Construct a histogramn Create and in
2、terpret bar charts, pie charts, and scatter diagramsn Present and interpret category data in bar charts and pie chartsn Describe appropriate and inappropriate ways to display data graphically2-3Organizing and Presenting Data Graphicallyn Data in raw form are usually not easy to use for decision maki
3、ngn Some type of organization is neededn Tablen Graphn Techniques reviewed here:n Ordered Arrayn Stem-and-Leaf Displayn Frequency Distributions and Histogramsn Bar charts and pie chartsn Contingency tables2-4Tables and Charts forNumerical DataNumerical DataOrdered ArrayStem-and-LeafDisplay Histogram
4、 Polygon OgiveFrequency Distributions andCumulative Distributions2-5The Ordered ArrayA sorted list of data: Shows range (min to max) Provides some signals about variability within the range May help identify outliers (unusual observations) If the data set is large, the ordered array is less useful2-
5、6n Data in raw form (as collected): 24, 26, 24, 21, 27, 27, 30, 41, 32, 38n Data in ordered array from smallest to largest:21, 24, 24, 26, 27, 27, 30, 32, 38, 41(continued)The Ordered Array2-7Stem-and-Leaf Diagramn A simple way to see distribution details in a data setMETHOD: Separate the sorted dat
6、a seriesinto leading digits (the stem) andthe trailing digits (the leaves)2-8Examplen Here, use the 10s digit for the stem unit:Data in ordered array:21, 24, 24, 26, 27, 27, 30, 32, 38, 41n 21 is shown asn 38 is shown asStem Leaf2 13 82-9Examplen Completed stem-and-leaf diagram:Stem Leaves2 1 4 4 6 7 73 0 2 84 1 (continued)Data in ordered array:21, 24, 24, 26, 27, 27, 30, 32, 38, 412-10Using other stem unitsn Using the 100s digit as the stem:n Round off the 10s digit to form the leavesn 613 would become 6 1n 776 would become 7 8n . . .n 1224 becomes 12 2 Stem Leaf
