condition mean min max ZT0-3 7.504967499999999 7.307575 7.70236 ZT4-7 9.80602 9.80602 9.80602 ZT8-11 8.067905 8.067905 8.067905 ZT12-15 0 0 0 ZT16-19 10.198405 10.198405 10.198405 ZT20-23 11.224599999999999 11.224599999999999 11.224599999999999