condition mean min max ZT0-3 2.50003532625 1.320831633 3.6792390195 ZT4-7 5.500148823 5.2554557195000005 5.7448419264999995 ZT8-11 6.74399963075 5.695397978500001 7.792601283 ZT12-15 7.1149087405 6.533362235 7.696455245999999 ZT16-19 7.409579494999999 6.892758911 7.9264000789999995 ZT20-23 10.11010956675 8.862656590499999 11.357562543