condition mean min max ZT0-3 19.2526 19.2526 19.2526 ZT4-7 16.67975 16.67975 16.67975 ZT8-11 15.04315 15.04315 15.04315 ZT12-15 19.81575 19.81575 19.81575 ZT16-19 20.13035 20.13035 20.13035 ZT20-23 18.304850000000002 18.304850000000002 18.304850000000002