condition mean min max ZT0-3 7.44602 7.44602 7.44602 ZT4-7 6.97631 6.97631 6.97631 ZT8-11 5.021045 5.021045 5.021045 ZT12-15 6.304145 6.304145 6.304145 ZT16-19 6.05229 6.05229 6.05229 ZT20-23 7.565245 7.565245 7.565245