condition mean min max ZT0-3 8.351727499999999 7.88809 8.815365 ZT4-7 7.939515 7.939515 7.939515 ZT8-11 6.7652 6.7652 6.7652 ZT12-15 0 0 0 ZT16-19 8.665865 8.665865 8.665865 ZT20-23 11.03905 11.03905 11.03905