condition mean min max ZT0-3 12.679273333333333 9.39622 14.813600000000001 ZT4-7 7.771405000000001 7.771405000000001 7.771405000000001 ZT8-11 10.908835 10.908835 10.908835 ZT12-15 19.5043 19.4239 19.584699999999998 ZT16-19 13.186399999999999 13.186399999999999 13.186399999999999 ZT20-23 15.5657 15.5657 15.5657