condition mean min max ZT0-3 206.685228 206.685228 206.685228 ZT4-7 256.2260715 256.2260715 256.2260715 ZT8-11 321.27727200000004 321.27727200000004 321.27727200000004 ZT12-15 297.21076 297.21076 297.21076 ZT16-19 303.730772 303.730772 303.730772 ZT20-23 282.147911 282.147911 282.147911