Percentile (Linear Interpolation)

Problem

Return the p-th percentile (0 <= p <= 100) using linear interpolation between closest ranks: rank = p/100 * (n-1), then interpolate between the sorted values at floor(rank) and ceil(rank). Return the single value when n = 1 and 0.0 for empty input.

Hint

The interpolation fraction is rank minus its floor.

Test cases

case 1

in: [[1,2,3,4,5],50]

expected: 3

case 2

in: [[1,2,3,4],25]

expected: 1.75

case 3

in: [[10,20,30,40],75]

expected: 32.5

case 4

in: [[5],90]

expected: 5

case 5

in: [[1,2,3,4,5,6,7,8,9,10],90]

expected: 9.1

Starter codePython

def percentile(data, p):
    # Your code here
    pass

5 test cases · run your code against them in the editor