condition mean min max ZT0-3 8.385945 8.38129 8.3906 ZT4-7 6.41975 6.41975 6.41975 ZT8-11 10.044905 10.044905 10.044905 ZT12-15 0 0 0 ZT16-19 13.93705 13.93705 13.93705 ZT20-23 9.505595 9.505595 9.505595