condition mean min max ZT0-3 8.429053333333334 6.853985 9.618055 ZT4-7 6.3626000000000005 6.3626000000000005 6.3626000000000005 ZT8-11 8.39985 8.39985 8.39985 ZT12-15 11.087822500000001 10.023945000000001 12.1517 ZT16-19 12.69885 12.69885 12.69885 ZT20-23 11.3265 11.3265 11.3265