Chapt.%204

# Essentials of Statistics for the Behavioral Science

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Chapter 4 Variability

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Introduction Variability - how much do individual scores differ from each other in a distribution. Variability is often considered “measurement error” or “statistical error”. The Mean may our best estimate of a characteristic – but it isn’t exact for everyone.

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Question
Introduction Different sets of data can have the same mean and still be quite different. A B 10 20 45 28 30 31 12 30 46 29 30 31 13 41 52 29 30 32 16 45 29 31 Mean of Both = 30 Mdn of Both = 30

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Potential Measures of Variability Range - The mathematical difference between the highest and lowest values in our distribution. * The range can accurately describe the difference between some distributions but not others. But, the range only takes two values into account. * ADD 1.0 for continuous numbers.
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Potential Measures of Variability Deviation Scores - the difference between the individual scores in a distribution and the mean of the distribution. Consider the following set of five numbers:
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Chapt.%204 - Chapter4 Variability Introduction Variability...

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