condition mean min max ZT0-3 8.167605 8.167605 8.167605 ZT4-7 7.159285000000001 7.159285000000001 7.159285000000001 ZT8-11 7.1903500000000005 7.1903500000000005 7.1903500000000005 ZT12-15 6.385854999999999 6.385854999999999 6.385854999999999 ZT16-19 8.2697 8.2697 8.2697 ZT20-23 8.47081 8.47081 8.47081