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HL Unit 9 (Probability)
Figure 9.15: Symmetric Box-andWhisker Plot
Figure 9.16: Skewed Box-andWhisker Plot
Box-and-Whiskers Plot The box extends from Q1 to Q3 with a dividing line at the median, covering the middle two quarters of data. The whiskers cover the upper and lower quarters of data.
Example 9.7.25 The box plot shown in Figure 9.15 shows a distribution summarized by a five-number summary: Q1 , Q2 , Q3 , xs , xl . Determine from the plot: interquartile range, median, range, and whether the distribution is symmetric or skewed.[2]
The interquartile range is 4 sec, from 13 sec to 17 sec. The median is 15 sec. The range is 10 sec, from 10 sec to 20 sec. The distribution is symmetric.
Example 9.7.26 The box plot shown in Figure 9.16 shows a distribution summarized by a five-number summary: Q1 , Q2 , Q3 , xs , xl . Determine from the plot: interquartile range, median, range, and whether the distribution is symmetric or skewed.[2]
The interquartile range is 0.2 kg, from 2.6 kg to 2.8 kg. The median is about 2.65 kg, and the range is 1.0 kg. The distribution is skewed. Mr. Budd, compiled September 29, 2010