EXAMPLE - Percentile Functions
This example illustrates you to apply percentile functions.
Functions:
Item | Description |
|---|---|
MEDIAN Function | Computes the median from all row values in a column or group. Input column can be of Integer or Decimal. |
PERCENTILE Function | Computes a specified percentile across all row values in a column or group. Input column can be of Integer or Decimal. |
QUARTILE Function | Computes a specified quartile across all row values in a column or group. Input column can be of Integer or Decimal. |
APPROXIMATEMEDIAN Function | Computes the approximate median from all row values in a column or group. Input column can be of Integer or Decimal. |
APPROXIMATEPERCENTILE Function | Computes an approximation for a specified percentile across all row values in a column or group. Input column can be of Integer or Decimal. |
APPROXIMATEQUARTILE Function | Computes an approximation for a specified quartile across all row values in a column or group. Input column can be of Integer or Decimal. |
Source:
The following table lists each student's height in inches:
Student | Height |
|---|---|
1 | 64 |
2 | 65 |
3 | 63 |
4 | 64 |
5 | 62 |
6 | 66 |
7 | 66 |
8 | 65 |
9 | 69 |
10 | 66 |
11 | 73 |
12 | 69 |
13 | 69 |
14 | 61 |
15 | 64 |
16 | 61 |
17 | 71 |
18 | 67 |
19 | 73 |
20 | 66 |
Transformation:
Use the following transformations to calculate the median height in inches, a specified percentile and the first quartile.
The first function uses a precise algorithm which can be slow to execute across large datasets.
The second function uses an appropriate approximation algorithm, which is much faster to execute across large datasets.
These approximate functions can use an error boundary parameter, which is set to
0.4(0.4%) across all functions.
Median: This transformation calculates the median value, which corresponds to the 50th percentile.
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | median(heightIn) |
Parameter: New column name | 'medianIn' |
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | approximatemedian(heightIn, 0.4) |
Parameter: New column name | 'approxMedianIn' |
Percentile: This transformation calculates the 68th percentile.
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | percentile(heightIn, 68, linear) |
Parameter: New column name | 'percentile68In' |
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | approximatepercentile(heightIn, 68, 0.4) |
Parameter: New column name | 'approxPercentile68In' |
Quartile: This transformation calculates the first quartile, which corresponds to the 25th percentile.
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | quartile(heightIn, 1, linear) |
Parameter: New column name | 'percentile25In' |
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | approximatequartile(heightIn, 1, 0.4) |
Parameter: New column name | 'approxPercentile25In' |
Results:
studentId | heightIn | approxPercentile25In | percentile25In | approxPercentile68In | percentile68In | approxMedianIn | medianIn |
|---|---|---|---|---|---|---|---|
1 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
2 | 65 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
3 | 63 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
4 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
5 | 62 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
6 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
7 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
8 | 65 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
9 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
10 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
11 | 73 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
12 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
13 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
14 | 61 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
15 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
16 | 61 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
17 | 71 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
18 | 67 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
19 | 73 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
20 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |