condition mean min max ZT0-3 8.6160675 7.987584999999999 9.24455 ZT4-7 9.194165 9.194165 9.194165 ZT8-11 8.97164 8.97164 8.97164 ZT12-15 0 0 0 ZT16-19 9.232285000000001 9.232285000000001 9.232285000000001 ZT20-23 9.811975 9.811975 9.811975