condition mean min max ZT0-3 2.452275 2.452275 2.452275 ZT4-7 1.91372 1.91372 1.91372 ZT8-11 1.514005 1.514005 1.514005 ZT12-15 1.890725 1.890725 1.890725 ZT16-19 2.43546 2.43546 2.43546 ZT20-23 2.16035 2.16035 2.16035