condition mean min max ZT0-3 6.4384125 5.157585 7.71924 ZT4-7 6.735609999999999 6.735609999999999 6.735609999999999 ZT8-11 7.529985 7.529985 7.529985 ZT12-15 0 0 0 ZT16-19 7.17293 7.17293 7.17293 ZT20-23 7.210725 7.210725 7.210725