condition mean min max ZT0-3 7.117615 7.117615 7.117615 ZT4-7 5.023715 5.023715 5.023715 ZT8-11 4.457055 4.457055 4.457055 ZT12-15 5.455534999999999 5.455534999999999 5.455534999999999 ZT16-19 6.422745 6.422745 6.422745 ZT20-23 6.12341 6.12341 6.12341