condition mean min max ZT0-3 2.9616225 2.86835 3.054895 ZT4-7 2.8731459999999998 2.8731459999999998 2.8731459999999998 ZT8-11 2.9028099999999997 2.9028099999999997 2.9028099999999997 ZT12-15 0 0 0 ZT16-19 3.90534 3.90534 3.90534 ZT20-23 3.621445 3.621445 3.621445