condition mean min max ZT0-3 10.839214 10.839214 10.839214 ZT4-7 12.28989 12.28989 12.28989 ZT8-11 13.8157655 13.8157655 13.8157655 ZT12-15 15.185839999999999 15.185839999999999 15.185839999999999 ZT16-19 11.551206 11.551206 11.551206 ZT20-23 11.749797000000001 11.749797000000001 11.749797000000001