Chapter1.1 - 1 Looking at Data-Distribution Let's play...

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1. Looking at Data-Distribution Let’s play Raisins Activity Give each student a small box of raisins for them to count the number of raisins in the box. Ask each student the number of raisins in your box Construct a display of the data called a dotplot . For example, here is a typical dotplot. 110 |** 111 |*** 112 |** 113 |***** 114 |****** 115 |*** 116 |** 117 |* Each dot(*) represents a single box of raisins.
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From this and any graphical display we can learn about several issues: 1.Where is the center, what is a typical number of raisins in a box? 2.What is the variation, how spread out are the values? 3.Shape of display In this chapter, we will be using tables and graphs used to summarize data. Why? Suppose the data set consists of million observations. It could be difficult to make sense of this data by only examining the million observations separately. If the data is summarized in an organized and meaningful manner, more information can be obtained from this summary than from examining the observations individually.
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1.1 Displaying Distributions with Graphs Sec.1.1 introduces several methods for exploring data. These methods should only be applied after clearly understanding the background of the data collected. The choice of method depends to some extent upon the type of variable being measured. The two types of variables described in this section are Categorical Variables - variables that record to what group or category an individual belongs. Hair color and gender are examples of categorical variables.
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This document was uploaded on 02/07/2012.

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Chapter1.1 - 1 Looking at Data-Distribution Let's play...

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