condition mean min max ZT0-3 251.300182 251.300182 251.300182 ZT4-7 982.2337275 982.2337275 982.2337275 ZT8-11 1134.5276495 1134.5276495 1134.5276495 ZT12-15 685.9856485 685.9856485 685.9856485 ZT16-19 507.50968800000004 507.50968800000004 507.50968800000004 ZT20-23 407.3578585 407.3578585 407.3578585