condition mean min max ZT0-3 12.600934 12.600934 12.600934 ZT4-7 12.3281475 12.3281475 12.3281475 ZT8-11 11.485487 11.485487 11.485487 ZT12-15 11.5515245 11.5515245 11.5515245 ZT16-19 11.9026935 11.9026935 11.9026935 ZT20-23 14.0278195 14.0278195 14.0278195