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Outliers
Numbers that are "out of line" relative to other numbers being examined in a set (list) of numbers.
In a set of numbers, some numbers are grouped relatively tightly together, and a couple of the numbers are far away from the group ... the numbers that are far from the group are called "outliers."
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Have you ever heard the idiom "out of the ball park." This idiom is used when you find something out of range, unreasonably, or inconsistent. The phrase came from the idea that some baseballs are hit within the field area, but, some balls are hit out of the stadium ... beyond the normal expectations.
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The following are examples of things that are "out of the ball park:"
In math, we have a special name for things that are well out of the normal, or anticipated value for something. We call something that is out of the ball park, an "OUTLIER." When you look at a list of things, there can be more than one outlier. Unfortunately, there is no accurate way to identify when something is out of the ball park. Everyone has their own method. Use your gut feelings and see if you can identify things that are outliers. The following sets of number give you a chance of recognizing outliers:
It is important to recognize outliers. If we do not recognize outliers, information can be affected during statistical examination. For example, in the following example the outliers would unreasonably skew the results. What is the student mean if the students earned the following grades on a quiz: 100, 100, 96, 96, 96, 100, 93, 93, 10, 27. Answer: 81. However, throwing out the outliers in the previous list, we have 100, 100, 96,96, 96,100,93,93 and an mean of about 97 (96.75). A mean of 97 is far more representative of the result for the majority of the students.
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| Identify the outliers in the following sets of numbers: | |
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