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

r<=28 200 211.4 0.617 0.617
r=29 5108 5134.0 0.132 0.748
r=30 23233 23103.0 0.731 1.479
r=31 11459 11551.5 0.741 2.220

chi-square = 2.220 with df = 3; p-value = 0.528