condition mean min max ZT0-3 3.136635 3.136635 3.136635 ZT4-7 1.436555 1.436555 1.436555 ZT8-11 2.072565 2.072565 2.072565 ZT12-15 4.541634999999999 4.541634999999999 4.541634999999999 ZT16-19 5.18139 5.18139 5.18139 ZT20-23 4.40084 4.40084 4.40084