condition mean min max ZT0-3 12.120775 12.120775 12.120775 ZT4-7 16.0626835 16.0626835 16.0626835 ZT8-11 15.680124500000002 15.680124500000002 15.680124500000002 ZT12-15 16.1360475 16.1360475 16.1360475 ZT16-19 14.2414135 14.2414135 14.2414135 ZT20-23 15.4555475 15.4555475 15.4555475