condition mean min max ZT0-3 8.420425 7.484970000000001 9.355879999999999 ZT4-7 8.436645 8.436645 8.436645 ZT8-11 9.46883 9.46883 9.46883 ZT12-15 0 0 0 ZT16-19 10.392389999999999 10.392389999999999 10.392389999999999 ZT20-23 8.833745 8.833745 8.833745