condition mean min max ZT0-3 2.237232 2.237232 2.237232 ZT4-7 1.0746565000000001 1.0746565000000001 1.0746565000000001 ZT8-11 1.7613898333333333 1.7613898333333333 1.7613898333333333 ZT12-15 1.372874 1.372874 1.372874 ZT16-19 1.617796 1.617796 1.617796 ZT20-23 0.8259705 0.8259705 0.8259705