Date: Wed, 19 Jan 2022 06:00:28 +0000 (GMT) Message-ID: <2089101752.105576.1642572028016@9c5033e110b2> Subject: Exported From Confluence MIME-Version: 1.0 Content-Type: multipart/related; boundary="----=_Part_105575_1661315724.1642572028016" ------=_Part_105575_1661315724.1642572028016 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Location: file:///C:/exported.html STDEVSAMP Function

STDEVSAMP Function

Computes the standard deviation across column values of Int= eger or Decimal type=20 using the sample statistical method.

The standard deviation of a set of values attempts to m= easure the spread in values around the mean and is used to measure confiden= ce in statistical results. A standard deviation of zero means that all valu= es are the same, and a small standard deviation means that the values are c= losely bunched together. A high value for standard deviation indicates that= the numbers are spread out widely. Standard deviation is always a positive= value.

NOTE: This function applies to a sample of the entire p= opulation. More information is below.

Terms...
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Relevant terms:

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TermDescription
PopulationPopulation statistical functions are computed fr= om all possible values. See https://en.wikip= edia.org/wiki/Statistical_population.
Sample=20
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Sample-based statistical functions are computed from a subset or sample = of all values. See https://en.wikipedia.org/w= iki/Sampling_(statistics).

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These function names include SAMP in their name.

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NOTE: Statistical sampling has no relationship to the = samples taken within the product. When statistical functions are computed d= uring job execution, they are applied across the entire dataset. Sample met= hod calculations are computed at that time.

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If a row contains a missing or null value, it is not factored into the c= alculation. If no numeric values are detected in the input column, the func= tion returns 0.

The square of standard deviation is variance. See VAR Function.

For a version of this function computed over a rolling window of rows, s= ee ROLLINGSTDEV Function.

Basic Usage=

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stdevsamp(myRating)

Output: Returns the standard deviation= of the values from the myRating column using the sample metho= d of calculation.

Sy= ntax and Arguments

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stdevsamp(col_ref) [group:group_col_ref] [= limit:limit_count]

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Argument Required? Data Type Description
function_col_ref Y string Name of column to which to apply the funct= ion

For more information on syntax standards, see Language Documentation Syntax Note= s.

col_ref

Name of the column whose values you wish to use in the calculation. Colu= mn must be a numeric (Integer or Decimal) type.

• Literal values are not supported as inputs.
• Multiple columns and wildcards are not supported.

Usage Notes:

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Required? Data Type Example Value
Yes String (column reference) myValues

Examples

This example shows some of the statistical functions that use the= sample method of computation. These include:

Source:

Students took tests on three consecutive Saturdays:

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Student Date Score
Andrew 11/9/19 81
Bella 11/9/19 84
Christina 11/9/19 79
David 11/9/19 64
Ellen 11/9/19 61
Fred 11/9/19 63
Andrew 11/16/19 73
Bella 11/16/19 88
Christina 11/16/19 78
David 11/16/19 67
Ellen 11/16/19 87
Fred 11/16/19 90
Andrew 11/23/19 76
Bella 11/23/19 93
Christina 11/23/19 81
David 11/23/19 97
Ellen 11/23/19 97
Fred 11/23/19 91

Transformation:

You can use the following transformations to calculate standard deviatio= n and variance across all dates using the sample method. Each computation h= as been rounded to three digits.

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Transformation Name <= code>New formula Single row formula round(stdevsamp(Score), 3) 'stdevSamp'
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Transformation Name <= code>New formula Single row formula round(varsamp(Score), 3) 'varSamp'
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You can use the following to limit the previous statistical computations= to the last two Saturdays of testing:

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Transformation Name <= code>New formula Single row formula round(stdevsampif(Score, Date !=3D '11\/9\= /2019'), 3) 'stdevSampIf'
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Transformation Name <= code>New formula Single row formula round(varsampif(Score, Date !=3D '11\/9\/2= 019'), 3) 'varSampIf'
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Results:

Student Date Score varSampIf stdevSampIf varSamp stdevSamp
Andrew 11/9/19 81 94.515 9.722 131.673 11.475
Bella 11/9/19 84 94.515 9.722 131.673 11.475
Christina 11/9/19 79 94.515 9.722 131.673 11.475
David 11/9/19 64 94.515 9.722 131.673 11.475
Ellen 11/9/19 61 94.515 9.722 131.673 11.475
Fred 11/9/19 63 94.515 9.722 131.673 11.475
Andrew 11/16/19 73 94.515 9.722 131.673 11.475
Bella 11/16/19 88 94.515 9.722 131.673 11.475
Christina 11/16/19 78 94.515 9.722 131.673 11.475
David 11/16/19 67 94.515 9.722 131.673 11.475
Ellen 11/16/19 87 94.515 9.722 131.673 11.475
Fred 11/16/19 90 94.515 9.722 131.673 11.475
Andrew 11/23/19 76 94.515 9.722 131.673 11.475
Bella 11/23/19 93 94.515 9.722 131.673 11.475
Christina 11/23/19 81 94.515 9.722 131.673 11.475
David 11/23/19 97 94.515 9.722 131.673 11.475
Ellen 11/23/19 97 94.515 9.722 131.673 11.475
Fred 11/23/19 91 94.515 9.722 131.673 11.475
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