condition mean min max ZT0-3 11.141525 10.677 11.60605 ZT4-7 6.6919699999999995 6.6919699999999995 6.6919699999999995 ZT8-11 7.062835 7.062835 7.062835 ZT12-15 0 0 0 ZT16-19 8.06274 8.06274 8.06274 ZT20-23 10.97065 10.97065 10.97065