condition mean min max ZT0-3 6.771411666666666 2.34276 9.221544999999999 ZT4-7 2.851515 2.851515 2.851515 ZT8-11 1.3711764999999998 1.3711764999999998 1.3711764999999998 ZT12-15 3.147075 2.70351 3.59064 ZT16-19 3.9796050000000003 3.9796050000000003 3.9796050000000003 ZT20-23 7.246425 7.246425 7.246425