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

r<=21 220 210.9 0.389 0.389
r=22 5247 5135.9 2.403 2.792
r=23 22973 23103.6 0.739 3.531
r=24 11560 11549.5 0.010 3.541

chi-square = 3.541 with df = 3; p-value = 0.315532