RANK OBSERVED EXPECTED (O-E)^2/E SUM

r<=28 218 211.4 0.205 0.205
r=29 5167 5134.0 0.212 0.417
r=30 23208 23103.0 0.477 0.894
r=31 11407 11551.5 1.808 2.702

chi-square = 2.702 with df = 3; p-value = 0.440