condition mean min max ZT0-3 1596.705479 1596.705479 1596.705479 ZT4-7 1982.1794315000002 1982.1794315000002 1982.1794315000002 ZT8-11 2112.9831965 2112.9831965 2112.9831965 ZT12-15 2249.4217215 2249.4217215 2249.4217215 ZT16-19 1948.0898905 1948.0898905 1948.0898905 ZT20-23 1397.253429 1397.253429 1397.253429