condition mean min max ZT0-3 86.8807577075 83.11360299 90.64791242499999 ZT4-7 69.039919635 66.257391185 71.822448085 ZT8-11 49.8022668275 44.95684566 54.647687995 ZT12-15 15.47120575975 8.999351884500001 21.943059634999997 ZT16-19 7.805755153 7.256156249 8.355354057 ZT20-23 14.391611517500001 11.97462518 16.808597855000002