condition mean min max ZT0-3 7.280951666666667 5.75395 9.905655 ZT4-7 5.767424999999999 5.767424999999999 5.767424999999999 ZT8-11 9.863745 9.863745 9.863745 ZT12-15 6.4750825 6.4291 6.521065 ZT16-19 5.590065 5.590065 5.590065 ZT20-23 12.767205 12.767205 12.767205