STATISTICAL PARAMETERS

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When looking at sample data, three statistical parameters are often measured: Mean, Median & Mode.

Arithmetic Mean

Calculated by:

This is related to the Expected Value of the data.

The mean is one way to think of the center of the data. Think of unit weight masses on a line. One mass at the location equal to the value of each data point, x (make sure to put multiple masses on any point where there are multiple occurances of that outcome). The Mean of the data is the point on the line where you should put your finger to make the masses balance. This balancing point is also called the centroid.
See SeeSaw Activities by the Calculus group in Project Links for more information on Centroids.

Median

The value in an ordered set of values below and above which there is an equal number of values or which is the arithmetic mean of the two middle values if there is no one middle number.

This is another type of the center of the data set.

Mode

The most frequently occuring value of a set of data.

When considering the theoretical aspect of a random variable, the Mode is the value of a random variable for which a function of probabilities defined on it achieves a relative maximum.

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RELATED
CONCEPTS

Random Variables
Probability Density Function
Expectation of a Continuous Random Variable
Expectation of Discrete Random Variables
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