condition mean min max ZT0-3 8.02641 8.02641 8.02641 ZT4-7 7.78944 7.78944 7.78944 ZT8-11 7.83809 7.83809 7.83809 ZT12-15 7.890373333333334 7.890373333333334 7.890373333333334 ZT16-19 8.03104 8.03104 8.03104 ZT20-23 8.167440000000001 8.167440000000001 8.167440000000001