condition mean min max ZT0-3 7.0407815131666664 6.340549344333334 7.741013681999999 ZT4-7 7.2089502485 6.7079189690000005 7.709981527999999 ZT8-11 7.879250965666667 7.60123094 8.157270991333334 ZT12-15 8.688640997666667 8.381699133333333 8.995582862000001 ZT16-19 7.8290395749999995 7.522643147 8.135436002999999 ZT20-23 7.031274918666666 6.999488111 7.063061726333333