condition mean min max ZT0-3 17.98574 17.98574 17.98574 ZT4-7 18.355878500000003 18.355878500000003 18.355878500000003 ZT8-11 15.863691 15.863691 15.863691 ZT12-15 16.771500500000002 16.771500500000002 16.771500500000002 ZT16-19 19.524044500000002 19.524044500000002 19.524044500000002 ZT20-23 19.543297000000003 19.543297000000003 19.543297000000003