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

r<=28 217 211.4 0.147 0.147
r=29 5162 5134.0 0.153 0.300
r=30 23206 23103.0 0.459 0.759
r=31 11415 11551.5 1.614 2.372

chi-square = 2.372 with df = 3; p-value = 0.499