Additive Seasonal Deviations

Problem

Estimate additive seasonal deviations by averaging each seasonal position separately and subtracting the overall series mean. Return one deviation per season, in season order 0 through m-1.

Return an empty list when m is not positive or m exceeds the series length.

Hint

These deviations sum to zero, so they never shift the overall level.

Test cases

case 1

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

expected: [-1,1]

case 2

in: [[5,5,5,5],2]

expected: [0,0]

case 3

in: [[0,6],2]

expected: [-3,3]

case 4

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

expected: []

case 5

in: [[],2]

expected: []

Starter codePython

def additive_seasonal_deviations(series, m):
    # Your code here
    pass

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