condition mean min max ZT0-3 0.226877 0.226877 0.226877 ZT4-7 0.2956315 0.2956315 0.2956315 ZT8-11 0.0802545 0.0802545 0.0802545 ZT12-15 0.2280295 0.2280295 0.2280295 ZT16-19 0.43330799999999997 0.43330799999999997 0.43330799999999997 ZT20-23 0.683888 0.683888 0.683888