condition mean min max ZT0-3 9.898793333333334 6.945655 12.682500000000001 ZT4-7 9.134045 9.134045 9.134045 ZT8-11 7.920975 7.920975 7.920975 ZT12-15 8.060955 6.27439 9.84752 ZT16-19 10.62844 10.62844 10.62844 ZT20-23 12.006450000000001 12.006450000000001 12.006450000000001