© 2016 Microsoft Corporation. All Rights Reserved. Chapter 42 Summarizing data by using descriptive statistics Questions answered in this chapter: •What defines a typical value for a data set? •How can I measure how much a data set spreads from its typical value? •Together, what do the mean and standard deviation of a data set tell me about the data? •How can I use descriptive statistics to compare data sets? •For a given data point, can I easily find its percentile ranking within the data set? For example, how can I find the ninetieth percentile of a data set? •How can I easily find the second largest or second smallest number in a data set? •How can I rank numbers in a data set? •What is the trimmed mean of a data set? •When I select a range of cells, is there an easy way to get a variety of statistics that describe the data in those cells? •Why do financial analysts often use the geometric mean to summarize the average return on a stock? •How can I use boxplots to summarize and compare datasets? In Chapter 41, “Summarizing data by using histograms and Pareto charts,” I showed how you can describe data sets by using histograms. In this chapter, I show how to describe a data set by using particular characteristics of the data, such as the mean, median, standard deviation, and variancemeasures that Microsoft Excel 2016 groups together as descriptive statistics. You can obtain the descriptive statistics for a set of data by clicking Data Analysis in the Analysis group on the Data tab (available as an add-in) and then selecting the Descriptive Statistics option. After you enter the relevant data and click OK, all the descriptive statistics of your data are displayed. You can also obtain descriptive statistics by using Excel functions. At the end of this chapter, I’ll show how boxplots can be used to summarize and compare data sets.
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