condition mean min max ZT0-3 10.71425 10.71425 10.71425 ZT4-7 6.5063949999999995 6.5063949999999995 6.5063949999999995 ZT8-11 8.33575 8.33575 8.33575 ZT12-15 11.898499999999999 11.898499999999999 11.898499999999999 ZT16-19 18.77995 18.77995 18.77995 ZT20-23 14.9139 14.9139 14.9139