condition mean min max ZT0-3 6.015795 6.015795 6.015795 ZT4-7 3.676415 3.676415 3.676415 ZT8-11 4.24806 4.24806 4.24806 ZT12-15 5.692185 5.692185 5.692185 ZT16-19 7.588010000000001 7.588010000000001 7.588010000000001 ZT20-23 5.908635 5.908635 5.908635