condition mean min max ZT0-3 7.718385 7.21819 8.21858 ZT4-7 7.120889999999999 7.120889999999999 7.120889999999999 ZT8-11 10.16151 10.16151 10.16151 ZT12-15 0 0 0 ZT16-19 10.61825 10.61825 10.61825 ZT20-23 8.684664999999999 8.684664999999999 8.684664999999999