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.

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

(2) Given {1, 2, 3, 4, 5, 6}; Determine

(3) Given {1, 2, 3, 4, 5, 6}; Determine