condition mean min max ZT0-3 9.192813 9.192813 9.192813 ZT4-7 8.2015845 8.2015845 8.2015845 ZT8-11 9.099969000000002 9.099969000000002 9.099969000000002 ZT12-15 9.6582235 9.6582235 9.6582235 ZT16-19 9.7285825 9.7285825 9.7285825 ZT20-23 9.6757375 9.6757375 9.6757375