1.4 Range, IQR, and Finding OutliersIn this section, we will discuss more measures of spread (or dispersion).Range: Max- MinPerventileso25thpercentile (or Q1)o50thpercentile (or Q2 or median)o75thpercentile (or Q3)IQR (interquartile range): Q3 - Q1The values of the minimum, Q1, Q2, Q3, and the maximum make up what is called our Five Number Summary.If we are given the five number summary, we can quickly find the range and IQR.Examples:1.)Twelve babies spoke for the first time at the following ages (in months):8, 9, 10, 11, 12, 13, 15, 15, 18, 20, 20, 26numbering→1 2 3 4 5 6 7 8 9 10 11 12Find Q1, Q2, Q3, the range, and the IQR.Range = 26 – 8 = 18Q2 = 13+152=14**there are two data sets in the middle, so we are going to have to average them**Q1 = 11+102=10.5**looking at data set number 1 thru 6, find the middle(since there are 2, we are going tohave to average them**Q3 = 20+182=19**looking at data set number 7 thru 12, find the middle(since there are 2, we are going tohave to average them**IQR = Q3 – Q1 = 19−10.5=8.5The IQR is used to determine data classified as

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