Bluman A.G. Elementary Statistics- A Step By Step Approach

Section 3–4 Exploratory Data Analysis 171Learning Center. If you have not installed this add-in, refer to the instructions in the ExcelStep by Step section of Chapter 1.To obtain a boxplot and stem and leaf plot:1. Enter the data values 33, 38, 43, 30, 29, 40, 51, 27, 42, 23, 31 into column A of a new Excelworksheet.2. Select the Add-Ins tab, then MegaStat from the toolbar.3. Select Descriptive Statistics from the MegaStat menu.4. Enter the cell range A1:A11 in the Input range.5. Check both Boxplot and Stem and Leaf Plot. Note: You may leave the other outputoptions unchecked for this example. Click [OK].The stem and leaf plot and the boxplot are shown below.Summary• This chapter explains the basic ways to summarize data. These include measures ofcentral tendency. They are the mean, median, mode, and midrange. The weightedmean can also be used. (3–1)• To summarize the variation of data, statisticians use measures of variation ordispersion. The three most common measures of variation are the range, variance,and standard deviation. The coefficient of variation can be used to compare thevariation of two data sets. The data values are distributed according to Chebyshev’stheorem on the empirical rule. (3–2)• There are several measures of the position of data values in the set. There arestandard scores, percentiles, quartiles, and deciles. Sometimes a data set containsan extremely high or extremely low data value, called an outlier. (3–3)• Other methods can be used to describe a data set. These methods are the five-numbersummary and boxplots. These methods are called exploratory data analysis. (3–4)The techniques explained in Chapter 2 and this chapter are the basic techniques usedin descriptive statistics.3–69