condition mean min max ZT0-3 12.908419 12.908419 12.908419 ZT4-7 14.9443835 14.9443835 14.9443835 ZT8-11 13.151285000000001 13.151285000000001 13.151285000000001 ZT12-15 12.1344265 12.1344265 12.1344265 ZT16-19 12.304927 12.304927 12.304927 ZT20-23 15.258315 15.258315 15.258315