Login

Contact Jeff

Email Updates
About
Stats Q&A
Calculators
Tutorials
Products
Home
View All Tutorials
The Standard Deviation :: Standard Deviation Calculation
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:
3, 4, 8, 11, 12, 17, 20
1
Add up all the values.
Sum
75
2
Count the total number of values.
n
7
3
Divide the Sum by the the total number of values.
Mean
10.7
4
Subtract the mean from each value. Then Square that result.
Value
ValueMean
(ValueMean)
^{2}
3
7.7
59.3
4
6.7
44.9
8
2.7
7.3
11
0.3
0.1
12
1.3
1.7
17
6.3
39.7
20
9.3
86.5
5
Add up all the squared deviations.
Sum of Squared Deviations
239.5
6
Divide the Sum of Squared Deviations by n1.
Sample Variance
39.9
7
Take the square root of the variance.
sample standard deviation
6.3
View All Tutorials
How well did you understand this lesson?
Avg. Rating 8.37 (161)
Not at all
Neutral
Extremely
0
1
2
3
4
5
6
7
8
9
10
What didn't make sense?
Name
Email
Not Published
Comment
To prevent comment spam, please answer the following question before submitting (tags not permitted) :
What is 4 + 4:
(enter the number)
September 9, 2013  Megan Garcia wrote:
why does the calculator say that 1212.9=0.9000000000000004 ?
February 2, 2013  Elsy wrote:
Great explanation, tools and visuals. Thank you.
June 12, 2012  Dennis wrote:
How do I divide in step 6
April 17, 2010  Marie wrote:
sample variance did not make sense. Divide the sum of squared deviations n1
September 21, 2009  anonomous wrote:
This was an excellent tutorial on stsndard deviation. Thank Y
September 15, 2009  Dave Mills wrote:
Excellent course! Thnak you!
March 18, 2009  Omar wrote:
Why do you divide the Sum of Squared Deviations by n1 to get the sample variance?