condition mean min max ZT0-3 17.9350043575 16.27713203 19.592876685 ZT4-7 18.892886265 17.63877888 20.14699365 ZT8-11 20.34303782166667 19.049539303333333 21.636536340000003 ZT12-15 19.373062115 18.353867746666666 20.392256483333334 ZT16-19 14.192953493000001 13.90491351 14.480993476 ZT20-23 15.585887284999998 14.77664284 16.39513173