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EXAMPLE - Statistical Functions Sample Method

This example shows some of the statistical functions that use the sample method of computation.

Functions:

Item

Description

STDEVSAMP Function

Computes the standard deviation across column values of Integer or Decimal type using the sample statistical method.

VARSAMP Function

Computes the variance among all values in a column using the sample statistical method. Input column can be of Integer or Decimal. If no numeric values are detected in the input column, the function returns 0.

STDEVSAMPIF Function

Generates the standard deviation of values by group in a column that meet a specific condition using the sample statistical method.

VARSAMPIF Function

Generates the variance of values by group in a column that meet a specific condition using the sample statistical method.

ROUND Function

Rounds input value to the nearest integer. Input can be an Integer, a Decimal, a column reference, or an expression. Optional second argument can be used to specify the number of digits to which to round.

Source:

Students took tests on three consecutive Saturdays:

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 deviation and variance across all dates using the sample method. Each computation has been rounded to three digits.

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

round(stdevsamp(Score), 3)

Parameter: New column name

'stdevSamp'

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

round(varsamp(Score), 3)

Parameter: New column name

'varSamp'

You can use the following to limit the previous statistical computations to the last two Saturdays of testing:

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

round(stdevsampif(Score, Date != '11\/9\/2019'), 3)

Parameter: New column name

'stdevSampIf'

Transformation Name

New formula

Parameter: Formula type

Single row formula

Parameter: Formula

round(varsampif(Score, Date != '11\/9\/2019'), 3)

Parameter: New column name

'varSampIf'

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