condition mean min max ZT0-3 11.2013 11.2013 11.2013 ZT4-7 6.1109100000000005 6.1109100000000005 6.1109100000000005 ZT8-11 7.710459999999999 7.710459999999999 7.710459999999999 ZT12-15 7.73514 7.73514 7.73514 ZT16-19 19.9728 19.9728 19.9728 ZT20-23 14.53465 14.53465 14.53465