NumDesc of data

# NumDesc of data - Numerical Descriptions of Data Central...

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Numerical Descriptions of Data Central Tendency Variation Shape Empirical Rule Relationship Excel 1. Central Tendency – Center of data Median Mode Mean or Average – 1.1 Sample Mean – Average of sample Symbol f8e5 X 1.2 Population Mean – Average of population Symbol, μ 2. Variation – Spread of data Range Variance 2.1 Population Variance Average squared distance values are from the center of the data Symbol, σ 2 2.2 Sample Variance Estimate of population variance Symbol S 2 Standard Deviation 2.3 Population standard deviation Square root of population variance Symbol, σ 2.4 Sample standard deviation Square root of sample variance Symbol, S 2.5 Example of use: http://www.businessofbaseball.com/yankeespayroll.htm (Also used in an example in section 5 of the notes)

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2.6 Calculation : a. Calculate the average of the values. b. Subtract the average from each value to see how far each value is from the average. c. Squaring each difference. d. Sum all the squared values e. i. For the population divide the sum by the number of values. ii. For the sample, divide by the number of values minus one. f. To find the standard deviation take the square root of the average in e. Both population and sample uses steps a-c and e. The difference between them occurs at step d Example: Calculate the population and sample standard deviations for a set of five numbers. Double Click on the Embedded Excel file below. Click the F9 function key to get new examples: (When finished click anywhere outside the worksheet) Step b. Step c.
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## This document was uploaded on 12/15/2011.

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NumDesc of data - Numerical Descriptions of Data Central...

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