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

r<=28 225 211.4 0.873 0.873
r=29 5084 5134.0 0.487 1.360
r=30 23057 23103.0 0.092 1.451
r=31 11634 11551.5 0.589 2.040

chi-square = 2.040 with df = 3; p-value = 0.564