condition mean min max ZT0-3 2.3758850000000002 2.3758850000000002 2.3758850000000002 ZT4-7 1.75154 1.75154 1.75154 ZT8-11 2.45268 2.45268 2.45268 ZT12-15 2.35763 2.35763 2.35763 ZT16-19 2.0895099999999998 2.0895099999999998 2.0895099999999998 ZT20-23 2.408255 2.408255 2.408255