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Standard Deviation Calculation
Home Introduction to the Standard Deviation Why do you need a measure of Variability? Measuring the Average Distance to the Mean Variability Quiz Population versus Sample Standard Deviation Standard Deviation Calculation Standard Deviation Calculation Short-Cut Method The Standard Deviation with Excel and The Online Calculator Standard Deviation in Practice Standard Deviation QuizView All Tutorials
 The Standard Deviation with Excel and The Online Calculator
The Standard Deviation :: Standard Deviation Calculation Short-Cut Method
This method might be a bit faster to calculate. Calculate the Standard Deviation for the following data using the calculator to the right (round to 1 decimal points). Click on the Check Answer button to see how you did.

Data: 1, 4, 11, 13, 17, 18, 21     Load another set of data

1Add up all the values.
Sum		 85
2Square this sum
Sum Squared		 7225
3Count the total number of values.
n 		7
4Divide Sum Squared by the the total number of values
Avg. Sum Squared		 1032.14
5Square each individual value. 
612 1
742 16
8112 121
9132 169
10172 289
11182 324
12212 441
13Add up all these squared values.
Sum of Squares		 1361
14Subtract Sum of Squares - Avg. Sum Squared 328.86
15Divide this by the total number of values minus 1.
sample variance		 54.81
16Take the square root of the variance.
sample standard deviation		 7.4

Check Answers

 
Standard Deviation Calculation
Home Introduction to the Standard Deviation Why do you need a measure of Variability? Measuring the Average Distance to the Mean Variability Quiz Population versus Sample Standard Deviation Standard Deviation Calculation Standard Deviation Calculation Short-Cut Method The Standard Deviation with Excel and The Online Calculator Standard Deviation in Practice Standard Deviation QuizView All Tutorials
 The Standard Deviation with Excel and The Online Calculator

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November 15, 2011 | sakura wrote:
how is this a shortcut? i already know how to use a calculator. the point of a shortcut was to find a way to get the standard deviation without having to go through the pain of having to square each individual value every single time! when you're working with 30+ numbers this is unbelievably irritating, calculator or no. this isn't a shortcut!
 
May 28, 2009 | brandee dungan wrote:
i do not understand where or how to get sample variance value. everything else makes since.