condition mean min max ZT0-3 5.0314483333333335 2.8964250000000002 6.869285 ZT4-7 5.33849 5.33849 5.33849 ZT8-11 5.76756 5.76756 5.76756 ZT12-15 3.5613400000000004 1.89371 5.22897 ZT16-19 7.0146250000000006 7.0146250000000006 7.0146250000000006 ZT20-23 6.501365 6.501365 6.501365