condition mean min max ZT0-3 2.8422805066666665 1.80138652 3.584285 ZT4-7 3.3329700000000004 3.3329700000000004 3.3329700000000004 ZT8-11 1.5511499999999998 1.5511499999999998 1.5511499999999998 ZT12-15 6.24979575 2.9426565 9.556935 ZT16-19 3.4004061292 3.4004061292 3.4004061292 ZT20-23 1.8766909999999999 1.8766909999999999 1.8766909999999999