condition mean min max ZT0-3 20.5181 20.5181 20.5181 ZT4-7 18.50475 18.50475 18.50475 ZT8-11 15.43845 15.43845 15.43845 ZT12-15 15.98675 15.98675 15.98675 ZT16-19 18.19035 18.19035 18.19035 ZT20-23 18.092 18.092 18.092