condition mean min max ZT0-3 4.0973524999999995 4.01204 4.182665 ZT4-7 3.53163 3.53163 3.53163 ZT8-11 7.427155 7.427155 7.427155 ZT12-15 0 0 0 ZT16-19 6.1407 6.1407 6.1407 ZT20-23 6.021425 6.021425 6.021425