condition mean min max ZT0-3 500.764426 500.764426 500.764426 ZT4-7 585.0055044999999 585.0055044999999 585.0055044999999 ZT8-11 679.0100669999999 679.0100669999999 679.0100669999999 ZT12-15 838.485492 838.485492 838.485492 ZT16-19 615.1151055 615.1151055 615.1151055 ZT20-23 481.7258545 481.7258545 481.7258545