condition mean min max ZT0-3 16.488712 16.488712 16.488712 ZT4-7 18.417152 18.417152 18.417152 ZT8-11 15.6395205 15.6395205 15.6395205 ZT12-15 15.0661185 15.0661185 15.0661185 ZT16-19 13.989097000000001 13.989097000000001 13.989097000000001 ZT20-23 13.831280499999998 13.831280499999998 13.831280499999998