Expected Counts Table

Problem

Return the table of expected counts for a 2D table of observed counts, where e_ij = row_total_i * col_total_j / total. Return [] for an empty table and a table of zeros when the total is zero.

Hint

Compute the row totals and column totals once, then divide their products by the grand total.

Test cases

case 1

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

expected: [[12,18],[28,42]]

case 2

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

expected: [[2,2,2],[2,2,2]]

case 3

in: [[[10,0],[0,10]]]

expected: [[5,5],[5,5]]

case 4

in: [[[0,0],[0,0]]]

expected: [[0,0],[0,0]]

case 5

in: [[[20,30,50]]]

expected: [[20,30,50]]

Starter codePython

def expected_counts(observed):
    # Your code here
    pass

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