condition mean min max ZT0-3 3.568143333333333 2.3369 4.333195 ZT4-7 4.428775 4.428775 4.428775 ZT8-11 4.044385 4.044385 4.044385 ZT12-15 6.33568 5.2195149999999995 7.4518450000000005 ZT16-19 5.540545 5.540545 5.540545 ZT20-23 2.9446000000000003 2.9446000000000003 2.9446000000000003