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Unformatted text preview: Chapter 10 Graphs, Good and Bad In this chapter • Pie chart • Bar graph • Line graph Pie chart We are now to the point in the class where we will begin looking at descriptive statistics. Remember that descriptive statistics are methods of summarizing a set of data. One way to do that is graphically. This chapter will introduce the most common graphs. The main reason statisticians use graphs is to look at the distribution of data. Distribution – all outcomes for a variable along with how often each outcome occurs The following data will be utilized in order to illustrate how some graphs work. The variable of interest in this illustration is type of operation (data was collected for a one year period from a single hospital) Type of operation Frequency Percentage Abdominal 115 23.1 Bones and joints 45 9.0 Eye, ear, nose, and throat 58 11.6 General 98 19.7 Neurosurgery 23 4.6 Other 65 13.1 Thoracic 20 4.0 Urologic 74 14.9 Total 498 100.0 Urologic 14.9% Thoracic 4.0% other 13.1% Neurosurgery 4.6% General 19.7% Eye, Ear, Nose, and Throat 11.6% Bones and Joints 9.0% Abdominal 23.1% Pie Chart of Operations First off we need to talk about the data presented. What type of data is this? You should answer qualitative data. The variable here is type of operation which yields non- numerical outcomes. With qualitative we are limited in the types of statistics available. The statistic will be based on either the frequency or the percentage of items in each category. Both of these quantities are included in the table....
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- Fall '10
- Statistics, line graph, Bar chart, random fluctuation, JFM MJ JAS, MJ JAS NDJFM MJ J