condition mean min max ZT0-3 12.066148 12.066148 12.066148 ZT4-7 14.733228 14.733228 14.733228 ZT8-11 15.689889999999998 15.689889999999998 15.689889999999998 ZT12-15 17.0574675 17.0574675 17.0574675 ZT16-19 13.9613595 13.9613595 13.9613595 ZT20-23 14.004952 14.004952 14.004952