condition mean min max ZT0-3 1.6641383333333335 1.26373 2.0908100000000003 ZT4-7 1.371295 1.371295 1.371295 ZT8-11 1.68098 1.68098 1.68098 ZT12-15 1.6915925 1.458185 1.925 ZT16-19 1.3911799999999999 1.3911799999999999 1.3911799999999999 ZT20-23 2.011755 2.011755 2.011755