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Summation Notation

 

Updated November 13, 2012

Summation notation is used in many statistical formulas. It is a notational device indicating addition and tells the user what should be added and the conditions for the addtion.

summation notation definition of parts

In statistics, the index numbers are usually omitted since all the data values are used.

Examples:
(1) Given the data: {1, 2, 3, 4, 5, 6}; Determine sum of x values

sum of x values example

(2) Given {1, 2, 3, 4, 5, 6}; Determine sum of x squared values form

sum of x squared values example

(3) Given {1, 2, 3, 4, 5, 6}; Determine sum of x values squared

sum of x values squared example