condition mean min max ZT0-3 14.827661 14.827661 14.827661 ZT4-7 19.750974499999998 19.750974499999998 19.750974499999998 ZT8-11 17.6518995 17.6518995 17.6518995 ZT12-15 14.4919395 14.4919395 14.4919395 ZT16-19 15.791639 15.791639 15.791639 ZT20-23 20.551796500000002 20.551796500000002 20.551796500000002