condition mean min max ZT0-3 1.6836346666666666 1.177779 2.495725 ZT4-7 1.274665 1.274665 1.274665 ZT8-11 0.6774975 0.6774975 0.6774975 ZT12-15 1.7586575 1.5938670000000001 1.923448 ZT16-19 1.7257349999999998 1.7257349999999998 1.7257349999999998 ZT20-23 1.479685 1.479685 1.479685