condition mean min max ZT0-3 7.147512 7.147512 7.147512 ZT4-7 8.8803015 8.8803015 8.8803015 ZT8-11 8.479053 8.479053 8.479053 ZT12-15 8.2498085 8.2498085 8.2498085 ZT16-19 7.910489999999999 7.910489999999999 7.910489999999999 ZT20-23 7.982537000000001 7.982537000000001 7.982537000000001