Lesson 8 - Shapes

A statistic is resistant if it is not affected by

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Unformatted text preview: tic is resistant if it is not affected by unusual values or skewness. Question: List 2 situations when the median is a better measure of the center than the mean. Answer: 1) when there are outliers and 2) when the data are skewed. The mean is affected more than the median by outliers and skewed data. With skewed data and outliers, the mean is “pulled” in the direction of the skewness or outliers. Because the median is not affected (or not affected as much), we say the median is resistant to skewed data and outliers. Example 8.1: Calculate the mean and median of the following 5 numbers: 1, 1, 1, 1, 1000. Notice how the one outlier (1000) is affecting the mean (mean = 200.8) while it’s not affecting the median at all (median = 1). The median does a better job describing the center of the data while the mean is not describing any data in this data set. Question: Describe a situation when neither the median nor the mean should be used to describe the center of the data. Answer: when the data are symmetric and bimodal, such as this: Example 8.2: Su...
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This document was uploaded on 02/15/2014 for the course STAT 351 at Oregon State.

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