# 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 New formula Single row formula median(heightIn) 'medianIn'
 Transformation Name New formula Single row formula approximatemedian(heightIn, 0.4) 'approxMedianIn'

Percentile: This transformation calculates the 68th percentile.

 Transformation Name New formula Single row formula percentile(heightIn, 68, linear) 'percentile68In'
 Transformation Name New formula Single row formula approximatepercentile(heightIn, 68, 0.4) 'approxPercentile68In'

Quartile: This transformation calculates the first quartile, which corresponds to the 25th percentile.

 Transformation Name New formula Single row formula quartile(heightIn, 1, linear) 'percentile25In'
 Transformation Name New formula Single row formula approximatequartile(heightIn, 1, 0.4) '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