condition mean min max ZT0-3 2.074648333333333 1.8016299999999998 2.380885 ZT4-7 1.627325 1.627325 1.627325 ZT8-11 3.889405 3.889405 3.889405 ZT12-15 5.1944275 4.82244 5.566415 ZT16-19 3.386085 3.386085 3.386085 ZT20-23 2.48568 2.48568 2.48568