condition mean min max ZT0-3 9.827839 9.827839 9.827839 ZT4-7 8.611137 8.611137 8.611137 ZT8-11 9.222242 9.222242 9.222242 ZT12-15 8.0759855 8.0759855 8.0759855 ZT16-19 9.707598 9.707598 9.707598 ZT20-23 9.3519095 9.3519095 9.3519095