STAT 101 Chapter Notes - Chapter 2: Interquartile Range, Box Plot, Quartile
2 Dec 2012
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Document Summary
Add their values and divide by the number of observations. Arrange all observations in order of size from smallest to largest. The mean and median of a roughly symmetric distribution are close together. If the distribution is exactly symmetric, the mean and median are exactly the same. In a skewed distribution, the mean is usually father out in the long tail than the median. Order the observations in increasing order and locate the median. First quartile the middle of the left side of the median. Lower quartile the middle of the right side of the median. Central box span of the first and third quartile. Line in the box marks the median. Lines extend from the box out to the smallest and largest observation. Boxplots show less detail than histograms and stemplots, best used for side-by-side comparison of multiple distributions. Interquartile range (iqr) the distance between the first and third quartile. 1. 5 x iqr = 1. 5 x 27. 5 = 41. 25.
