condition mean min max ZT0-3 17.122277 17.122277 17.122277 ZT4-7 21.66994 21.66994 21.66994 ZT8-11 20.6385345 20.6385345 20.6385345 ZT12-15 15.5225155 15.5225155 15.5225155 ZT16-19 15.3336515 15.3336515 15.3336515 ZT20-23 16.520808000000002 16.520808000000002 16.520808000000002