condition mean min max ZT0-3 3.27831845575 2.626422902 3.9302140095 ZT4-7 5.606807144999999 4.4178710335 6.7957432565 ZT8-11 13.6466619505 9.556909331 17.73641457 ZT12-15 13.18866019 11.758576085000001 14.618744295 ZT16-19 12.29313359 11.82593337 12.760333809999999 ZT20-23 10.961824712750001 10.6058843455 11.317765080000001