condition mean min max ZT0-3 13.55505 13.084399999999999 14.0257 ZT4-7 15.791 15.791 15.791 ZT8-11 16.10885 16.10885 16.10885 ZT12-15 0 0 0 ZT16-19 17.696350000000002 17.696350000000002 17.696350000000002 ZT20-23 19.14525 19.14525 19.14525