Compound Symmetry Check

Problem

Return True when a square covariance matrix has one common diagonal value and one common off-diagonal value within 1e-9, and False otherwise (including non-square or empty input).

Hint

Compound symmetry is the covariance structure assumed by repeated-measures ANOVA.

Test cases

case 1

in: [[[1,0.5],[0.5,1]]]

expected: true

case 2

in: [[[1,0.5],[0.5,2]]]

expected: false

case 3

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

expected: true

case 4

in: [[[2,1,0],[1,2,1],[0,1,2]]]

expected: false

case 5

in: [[]]

expected: false

Starter codePython

def compound_symmetry_check(matrix):
    # Your code here
    pass

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