condition mean min max ZT0-3 4.0805066666666665 2.60553 5.12148 ZT4-7 2.15246 2.15246 2.15246 ZT8-11 1.615425 1.615425 1.615425 ZT12-15 3.6734349999999996 2.892415 4.454454999999999 ZT16-19 3.145275 3.145275 3.145275 ZT20-23 4.923005 4.923005 4.923005