condition mean min max ZT0-3 8.9339720145 8.11579487 9.752149159 ZT4-7 7.1032704035 6.4404022515 7.7661385554999995 ZT8-11 8.5477258055 7.6048360285 9.4906155825 ZT12-15 7.776344910750001 7.589979142500001 7.962710679000001 ZT16-19 10.04025389175 8.3236677085 11.756840075 ZT20-23 16.9011488925 14.626128040000001 19.176169745