condition mean min max ZT0-3 4.20402 3.8346850000000003 4.43283 ZT4-7 4.0872399999999995 4.0872399999999995 4.0872399999999995 ZT8-11 3.9689699999999997 3.9689699999999997 3.9689699999999997 ZT12-15 6.4577225 6.180429999999999 6.735015000000001 ZT16-19 4.04757 4.04757 4.04757 ZT20-23 4.67424 4.67424 4.67424