condition mean min max ZT0-3 6.8420413 5.456122582999999 8.227960017000001 ZT4-7 7.51999059475 6.865099553 8.1748816365 ZT8-11 8.19158786925 8.0279881195 8.355187619 ZT12-15 9.35558354075 8.9058002655 9.805366816 ZT16-19 10.692591674 8.366910343 13.018273005000001 ZT20-23 20.35392983 16.62985968 24.07799998