condition mean min max ZT0-3 16.28686666666667 14.0359 18.40135 ZT4-7 9.79963 9.79963 9.79963 ZT8-11 6.7337 6.7337 6.7337 ZT12-15 12.36305 11.5093 13.2168 ZT16-19 15.01305 15.01305 15.01305 ZT20-23 19.9952 19.9952 19.9952