condition mean min max ZT0-3 6.3168875 5.935594999999999 6.69818 ZT4-7 6.08883 6.08883 6.08883 ZT8-11 6.9807500000000005 6.9807500000000005 6.9807500000000005 ZT12-15 0 0 0 ZT16-19 7.11082 7.11082 7.11082 ZT20-23 6.960525 6.960525 6.960525