condition mean min max ZT0-3 2.028305 2.028305 2.028305 ZT4-7 1.402885 1.402885 1.402885 ZT8-11 1.845195 1.845195 1.845195 ZT12-15 1.6544249999999998 1.6544249999999998 1.6544249999999998 ZT16-19 2.7024049999999997 2.7024049999999997 2.7024049999999997 ZT20-23 2.4676850000000004 2.4676850000000004 2.4676850000000004