You are not legally required to take a field sobriety test. These tests are unlike the chemical tests to determine your blood alcohol concentration [BAC].
When asked to take a chemical test by a police officer who has already arrested you, and if you refuse, there are serious consequences, i.e., loss of drivers license for a year.
Michigan has its has its own version of an implied consent law providing that a driver impliedly consents to alcohol testing just by the act of driving. A refusal to take a breath test is itself a civil violation subject to stiff penalties. For example, refusing a breath test at the police station will result in automatic drivers-license revocation for a period of one year.
During the period of an implied consent revocation, the refusing driver is denied all driving privileges, even driving related to work or school. In such a case, an experienced DUI attorney can schedule a Circuit Court hearing to request a limited purpose driver license during what would otherwise be a period of complete revocation of privileges.
In the overwhelming majority of cases individuals with no previous alcohol related driving offenses should willingly submit to a breath test request.
Remember, always be polite and courteous to the officer. If you are rude or become abusive or obstructive, the only person who is going to lose is you, not the police officer.