condition mean min max ZT0-3 1.19361 1.19361 1.19361 ZT4-7 2.4533899999999997 2.4533899999999997 2.4533899999999997 ZT8-11 1.8232849999999998 1.8232849999999998 1.8232849999999998 ZT12-15 0.507566 0.507566 0.507566 ZT16-19 0.5397295 0.5397295 0.5397295 ZT20-23 0.39697899999999997 0.39697899999999997 0.39697899999999997