condition mean min max ZT0-3 14.772751666666666 9.571105 18.6099 ZT4-7 7.990740000000001 7.990740000000001 7.990740000000001 ZT8-11 6.526705 6.526705 6.526705 ZT12-15 9.276187499999999 7.609225 10.94315 ZT16-19 12.77365 12.77365 12.77365 ZT20-23 19.6346 19.6346 19.6346