Thursday, January 10, 2013

Standard Deviation Computation

Introduction to standard deviation computation:

In statistics, the standard deviation shows about the statistical population, a data set, or a probability distribution is the square root of its variance. Standard deviation is a widely helps to measure the variability or dispersion, being algebraically more tractable though practically less robust than average absolute deviation. Standard deviation computation is for low standard deviation indicates that the data points tend to be very close to the mean, and computation for high standard deviation indicates that the data spread over a large range of values.

Standard Deviation Computation:

Standard deviation computation is used to clear the doubts in standard deviation. Tutor is the process of teaching/helping carried by a person who is expert in computation of deviation. Standard deviation helps us to clear our struggles and troubles through calculation. Standard deviation computation is used to clear our doubts in standard deviation. Please express your views of this topic homework help for math by commenting on blog.

Standard deviation formula involves two formulas are,

Mean and Standard deviation formula are given below.

Mean:   `barx` = `( sum(x) ) / n`

Standard deviation:   S =` sqrt(((sum(x - barx)^2)) / (n-1))`

Example Problems for Standard Deviation Computation:

The example problems for standard deviation computation are given below:

Example for standard deviation computation 1:

Find the standard deviation for the given set of numbers: { 71, 42, 63, 94, 115 }

Solution:

Step 1: Mean

Mean   =  ` ( 71 + 42 + 63 + 94 + 115 ) / 5`

=  ` 385 / 5`

=  77

Step 2: Variance

Variance  =   `( (71 - 77)^2 + (42 - 77)^2 + (63 - 77)^2 + (94 - 77)^2 + (115 - 77)^2 )/(5-1)`

=   `( (-6)^2 + (-35)^2 + (-14)^2 + (17)^2 + (38)^2 )/4`

=   `(3600+1225+196+289+1444)/4`

=   `6754/4`

=  1688.5

Step 3:Standard deviation

Standard deviation  =  `sqrt ( 1688.5 )`

=  41.091

Thus,  the standard deviation computation for finding the variance from the given data is computated.

Example for standard deviation computation 2:

Find the standard deviation for the given data set: { 15, 25, 20, 35, 30 }

Solution:

Step 1: Mean

Mean   =  ` ( 15 + 25 + 20 + 35 + 30 ) / 5`

=  ` 125 / 5`

=  25

Step 2: Variance

Variance  =   `( (15-25)^2 + (25-25)^2 + (20 - 25)^2 + (35-25)^2 + (30-25)^2 )/(5-1)`

=   `( (-10)^2 + (0)^2 + (-5)^2 + (10)^2 + (5)^2 )/4`

=   `(100 + 0 + 25 + 100 + 25)/4`

=   `150/4`

=   37.5

Step 3: Standard deviation

Standard deviation  =  `sqrt ( 37.5 )`

=  6.123

Thus,  the standard deviation computation for finding the varience from the given data is calculated.

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