condition mean min max ZT0-3 16.055983333333334 14.62605 17.0202 ZT4-7 21.6715 21.6715 21.6715 ZT8-11 11.911349999999999 11.911349999999999 11.911349999999999 ZT12-15 19.134099999999997 17.487299999999998 20.7809 ZT16-19 13.863050000000001 13.863050000000001 13.863050000000001 ZT20-23 8.560125 8.560125 8.560125