condition mean min max ZT0-3 20.239951 20.239951 20.239951 ZT4-7 11.75569 11.75569 11.75569 ZT8-11 11.8476885 11.8476885 11.8476885 ZT12-15 19.5460515 19.5460515 19.5460515 ZT16-19 14.133054000000001 14.133054000000001 14.133054000000001 ZT20-23 47.907195 47.907195 47.907195