condition mean min max ZT0-3 8.422852 8.422852 8.422852 ZT4-7 8.052329499999999 8.052329499999999 8.052329499999999 ZT8-11 8.843557 8.843557 8.843557 ZT12-15 8.916341500000001 8.916341500000001 8.916341500000001 ZT16-19 8.669061 8.669061 8.669061 ZT20-23 9.37463 9.37463 9.37463