An Explanation of Statistical Tools from DocumentingExcellence.com
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Descriptive Statistics

The purpose of these statistics is to summarize a common pattern for a group or classification. Descriptive statistics focus on two issues -- measures of central tendency and measures of dispersion.

How are the cases summarized?
An average of measurement of some variable a shared central level of values on this classification? In other words, descriptions that reduce the cases to a center point.

	Mode -- most occurring value. This average works best when there are a limited number of possible categories. For example, males and females. This average does not work well when measurement is quantitative. That is, when one is considering weight, or distance since in these examples the measurement can be part way between to points.
	Median -- the central case, one-half of the cases are higher and one-half are lower in a ranking. This average works well when we want the middle of a distribution with one-half the cases greater, and one half the cases less than the median. It is frequently used to measure income where having a few very, very rich individuals might draw the mean average up well above the point at which one half the population is richer and poorer.
	Median -- a value that is a the center of all values. This average is the middle of the values.

How are the cases dispersed?

	Minimum, Maximum, and Range
	Standard Deviation and Variance
	Other more advanced statistics including Skewness and Kurtosis.