condition mean min max ZT0-3 7.252192 7.252192 7.252192 ZT4-7 7.4771435 7.4771435 7.4771435 ZT8-11 7.2313125 7.2313125 7.2313125 ZT12-15 7.58329 7.58329 7.58329 ZT16-19 7.7273835 7.7273835 7.7273835 ZT20-23 7.5509474999999995 7.5509474999999995 7.5509474999999995