condition mean min max ZT0-3 4.549093333333333 3.06284 7.092745000000001 ZT4-7 3.50817 3.50817 3.50817 ZT8-11 4.198285 4.198285 4.198285 ZT12-15 6.947557499999999 5.953329999999999 7.941784999999999 ZT16-19 6.861835 6.861835 6.861835 ZT20-23 9.36644 9.36644 9.36644