condition mean min max ZT0-3 17.261775 16.59635 17.9272 ZT4-7 15.08435 15.08435 15.08435 ZT8-11 14.628599999999999 14.628599999999999 14.628599999999999 ZT12-15 0 0 0 ZT16-19 17.863599999999998 17.863599999999998 17.863599999999998 ZT20-23 17.485500000000002 17.485500000000002 17.485500000000002