condition mean min max ZT0-3 8.174074 8.174074 8.174074 ZT4-7 8.172739 8.172739 8.172739 ZT8-11 8.145828 8.145828 8.145828 ZT12-15 8.6954745 8.6954745 8.6954745 ZT16-19 7.877770999999999 7.877770999999999 7.877770999999999 ZT20-23 8.075811999999999 8.075811999999999 8.075811999999999