##### Page tree

Contents:

Registered users of this product or Trifacta Wrangler Enterprise should login to Product Docs through the application.

This example illustrates how you can apply statistical functions to your dataset. Calculations include average (mean), max, min, standard deviation, and variance.

Source:

Students took a test and recorded the following scores. You want to perform some statistical analysis on them:

StudentScore
Anna84
Ben71
Caleb76
Danielle87
Evan85
Faith92
Gabe86
Hannah99
Ian73
Jane68

Transform:

You can use the following transforms to calculate the average (mean), minimum, and maximum scores:

derive value:AVERAGE(Score) as:'avgScore'

derive value:MIN(Score) as:'minScore'

derive value:MAX(Score) as:'maxScore'

To apply statistical functions to your data, you can use the `VAR` and `STDEV` functions, which can be used as the basis for other statistical calculations.

derive value:VAR(Score)

derive value:STDEV(Score)

For each score, you can now calculate the variation of each one from the average, using the following:

derive value:((Score - average_Score) / stdev_Score) as:'stDevs'

Now, you want to apply grades based on a formula:

AstDevs > 1
BstDevs > 0.5
C-1 <= stDevs <= 0.5
DstDevs < -1
FstDevs < -2

You can build the following transform using the `IF` function to calculate grades.

derive value:IF((stDevs > 1),'A',IF((stDevs < -2),'F',IF((stDevs < -1),'D',IF((stDevs > 0.5),'B','C'))))

To clean up the content, you might want to apply some formatting to the score columns. The following reformats the `stdev_Score` and `stDevs` columns to display two decimal places:

set col:stdev_Score value:NUMFORMAT(stdev_Score, '##.00')

set col:stDevs value:NUMFORMAT(stDevs, '##.00')

Results:

Anna8482.16899

87.69000000000142

9.360.20C
Ben7182.1689987.690000000001429.36-1.19D
Caleb7682.1689987.690000000001429.36-0.65C
Danielle8782.1689987.690000000001429.360.52B
Evan8582.1689987.690000000001429.360.31C
Faith9282.1689987.690000000001429.361.06A
Gabe8682.1689987.690000000001429.360.42C
Hannah9982.1689987.690000000001429.361.80A
Ian7382.1689987.690000000001429.36-0.97C
Jane6882.1689987.690000000001429.36-1.51D