condition mean min max ZT0-3 5.062451666666667 4.055685 5.684340000000001 ZT4-7 2.8405299999999998 2.8405299999999998 2.8405299999999998 ZT8-11 3.038175 3.038175 3.038175 ZT12-15 5.7810475 5.366275 6.195819999999999 ZT16-19 3.6766949999999996 3.6766949999999996 3.6766949999999996 ZT20-23 4.744225 4.744225 4.744225