condition mean min max ZT0-3 6.489363333333333 5.476015 7.388055 ZT4-7 5.14893 5.14893 5.14893 ZT8-11 12.2853 12.2853 12.2853 ZT12-15 10.464115 9.76373 11.1645 ZT16-19 8.958355000000001 8.958355000000001 8.958355000000001 ZT20-23 8.010785 8.010785 8.010785