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

r<=28 238 211.4 3.342 3.342
r=29 5061 5134.0 1.038 4.380
r=30 23210 23103.0 0.495 4.876
r=31 11491 11551.5 0.317 5.193

chi-square = 5.193 with df = 3; p-value = 0.158