condition mean min max ZT0-3 1.643935 1.643935 1.643935 ZT4-7 1.36599 1.36599 1.36599 ZT8-11 1.51139 1.51139 1.51139 ZT12-15 2.093955 2.093955 2.093955 ZT16-19 2.43533 2.43533 2.43533 ZT20-23 1.613185 1.613185 1.613185