condition mean min max ZT0-3 15.841794 15.841794 15.841794 ZT4-7 18.3065745 18.3065745 18.3065745 ZT8-11 18.5490725 18.5490725 18.5490725 ZT12-15 17.2562945 17.2562945 17.2562945 ZT16-19 16.275758 16.275758 16.275758 ZT20-23 16.4988625 16.4988625 16.4988625