condition mean min max ZT0-3 15.87215 15.87215 15.87215 ZT4-7 12.6327 12.6327 12.6327 ZT8-11 14.3013 14.3013 14.3013 ZT12-15 14.95235 14.95235 14.95235 ZT16-19 16.5285 16.5285 16.5285 ZT20-23 15.8087 15.8087 15.8087