condition mean min max ZT0-3 7.125965000000001 7.125965000000001 7.125965000000001 ZT4-7 6.024905 6.024905 6.024905 ZT8-11 7.91027 7.91027 7.91027 ZT12-15 9.473939999999999 9.473939999999999 9.473939999999999 ZT16-19 8.421265 8.421265 8.421265 ZT20-23 7.51276 7.51276 7.51276