condition mean min max ZT0-3 16.561975 14.93845 18.1855 ZT4-7 20.7958 20.7958 20.7958 ZT8-11 20.25575 20.25575 20.25575 ZT12-15 0 0 0 ZT16-19 22.736849999999997 22.736849999999997 22.736849999999997 ZT20-23 17.8886 17.8886 17.8886