condition mean min max ZT0-3 13.449625 13.303249999999998 13.596 ZT4-7 17.22235 17.22235 17.22235 ZT8-11 24.872799999999998 24.872799999999998 24.872799999999998 ZT12-15 0 0 0 ZT16-19 29.3943 29.3943 29.3943 ZT20-23 20.70705 20.70705 20.70705