condition mean min max ZT0-3 9.45133 9.45133 9.45133 ZT4-7 11.6988 11.6988 11.6988 ZT8-11 7.5362599999999995 7.5362599999999995 7.5362599999999995 ZT12-15 7.8527249999999995 7.8527249999999995 7.8527249999999995 ZT16-19 7.43642 7.43642 7.43642 ZT20-23 7.5595 7.5595 7.5595