condition mean min max ZT0-3 16.806948333333334 9.515095 20.79225 ZT4-7 7.81703 7.81703 7.81703 ZT8-11 8.703315 8.703315 8.703315 ZT12-15 13.669649999999999 12.671949999999999 14.667349999999999 ZT16-19 14.10115 14.10115 14.10115 ZT20-23 24.0133 24.0133 24.0133