Altair® Panopticon

 

Stdev

The Standard Deviation of the selection.

The Standard Deviation is a measure of how spread-out numbers are in a set. The Deviation just means how far from the normal.

Stdev is used when the group of numbers being evaluated is only a partial sampling of the whole population.

The formula:

Where  is the mean computed by getting the sum of all the items and dividing them by the number of items minus one.


 

Sample 1

Given a set of numbers like 12, 6, 12.

Steps:

1.     Compute the mean of the sample.

Mean = (Sum of items/n), where n is the number of items

12+6+12/3=10

2.     Square the difference between each point and the mean

(12-10)^2 =4

(6-10)^2 =16

(12-10)^2 =4

3.     Calculate the average of the results in step 2 above

4+16+4/3-1=24/2

4.     Compute the square root of the result in step 4.

√12 or 3.4641

 

 

Sample 2:

Given the following sample fields:

Number

Arbitrary

Negative Values

Positive Values

One

Binary

Currency

Decimal

1

3

-1

1

1

0

$1.00

1.01

2

2

-2

2

 

1

$10.00

2.02

3

1

-3

3

 

0

$100.00

3.03

4

0

-4

4

 

1

$1,000.00

4.04

5

-1

-5

5

 

0

$10,000.00

5.05

6

-2

-6

6

 

1

-$1.00

6.06

7

-3

-7

7

 

0

-$10.00

7.07

8

0

-8

8

 

 

-$100.00

8.08

9

0

-9

9

 

 

-$1,000.00

9.09

10

0

-10

0

 

 

$0.00

0.00

Sample fields.

The Stdev for each field:

Number

Arbitrary

Negative Values

Positive Values

One

Binary

Currency

Decimal

3.0277

1.7638

3.0277

3.0277

0

.5345

$3,197.5720

3.0579

The results per field.