condition mean min max ZT0-3 5.323431666666667 1.206615 9.26304 ZT4-7 1.529465 1.529465 1.529465 ZT8-11 1.7120700000000002 1.7120700000000002 1.7120700000000002 ZT12-15 3.5169225 2.834625 4.19922 ZT16-19 6.6905850000000004 6.6905850000000004 6.6905850000000004 ZT20-23 8.50023 8.50023 8.50023