The standard deviation of the set 10, 11, 9, 11, 9) is
Answers
Step-by-step explanation:

Standard deviation (SD) measured the volatility or variability across a set of data. It is the measure of the spread of numbers in a data set from its mean value and can be represented using the sigma symbol (σ). The following algorithmic calculation tool makes it easy to quickly discover the mean, variance & SD of a data set.
Enter the numbers separated by comma ','
E.g: 11,21,10,42,53
Total Numbers
5
Mean (Average)
10
SD
1
Variance (SD)
1
Population SD
0.89443
Variance(Population SD)
0.8
Standard Deviation111110.89410.894101010109999Maximum SDMeanMinimum SDSamplePopulation010203040Highcharts.comMaximum SDPopulation: 10.894
Math Formulas
Mean = sum of values / N (number of values in set)
Variance = ((n1- Mean)2 + ... nn- Mean)2) / N-1 (number of values in set - 1)
Standard Deviation σ = √Variance
Population Standard Deviation = use N in the Variance denominator if you have the full data set. The reason 1 is subtracted from standard variance measures in the earlier formula is to widen the range to "correct" for the fact you are using only an incomplete sample of a broader data set.
Example Calculation
for data set 1,8,-4,9,6 compute the SD and the population SD.
SD Calculation
Sum:
1+8+-4+9+6=20
Mean:
20/5 numbers =
mean of 4
Variance:
((1-4)2 + (8-4)2 + (-4-4)2 + (9-4)2 + (6-4)2) / (N-1) =
((-3)2 +( 4)2 + (-8)2 + (5)2 + (2)2 ) / 4 =
(9+16+64+25+4)/4 =
118/4 = 29.5
Standard Deviation:
√29.5= 5.43139
Population SD Calculation
Population Standard Deviation Variance:
((1-4)2 + (8-4)2 + (-4-4)2 + (9-4)2 + (6-4)2) / N =
((-3)2 +( 4)2 + (-8)2 + (5)2 + (2)2 ) / 5 =
(9+16+64+25+4) / 5 =
118 / 5 = 23.6
Population Standard Deviation:
√23.6= 4.85798