Contents:
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 |
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