public function dataProviderForMeanSquares() { return [[[[1, 2], [2, 3], [4, 5], [5, 7], [6, 8]], [0, 0], ['mse' => 0.1201550388, 'msr' => 25.6395348837, 'mst' => 6.5, 'sd' => 0.3466338685]]]; }