condition mean min max ZT0-3 7.396920000000001 7.396920000000001 7.396920000000001 ZT4-7 7.325913333333334 7.325913333333334 7.325913333333334 ZT8-11 7.51185 7.51185 7.51185 ZT12-15 7.43885 7.43885 7.43885 ZT16-19 7.30356 7.30356 7.30356 ZT20-23 7.1754500000000005 7.1754500000000005 7.1754500000000005