condition mean min max ZT0-3 18.95736666666667 12.56165 23.31875 ZT4-7 7.427835 7.427835 7.427835 ZT8-11 6.000425 6.000425 6.000425 ZT12-15 12.8784 12.6492 13.1076 ZT16-19 12.2638 12.2638 12.2638 ZT20-23 20.68705 20.68705 20.68705