condition mean min max ZT0-3 7.527621 7.527621 7.527621 ZT4-7 8.4314275 8.4314275 8.4314275 ZT8-11 9.6031805 9.6031805 9.6031805 ZT12-15 9.6645975 9.6645975 9.6645975 ZT16-19 9.296316000000001 9.296316000000001 9.296316000000001 ZT20-23 10.506746499999998 10.506746499999998 10.506746499999998