condition mean min max ZT0-3 10.412257 10.412257 10.412257 ZT4-7 14.2331795 14.2331795 14.2331795 ZT8-11 12.557984000000001 12.557984000000001 12.557984000000001 ZT12-15 15.0166895 15.0166895 15.0166895 ZT16-19 13.5751215 13.5751215 13.5751215 ZT20-23 18.875428 18.875428 18.875428