condition mean min max ZT0-3 15.445309 15.445309 15.445309 ZT4-7 15.846729499999999 15.846729499999999 15.846729499999999 ZT8-11 16.9658315 16.9658315 16.9658315 ZT12-15 13.2662785 13.2662785 13.2662785 ZT16-19 15.518602 15.518602 15.518602 ZT20-23 14.8617755 14.8617755 14.8617755