A 3% margin of error means that if the same procedure is used a large number of times, 95% of the time the true population average will be within the 95% confidence interval of the sample estimate plus or minus 3%.
The latter is a fairly common problem which is associated with people who have the condition known as hypothyroidism. Despite what many people think, tinnitus is actually just a symptom of a larger underlying problem. Hypothyroidism is just one of the many health problems which can cause tinnitus to become a problem. In most cases when the thyroid dysfunction is treated, the tinnitus will resolve itself. There have been some cases of people with this condition who suffer from long-term tinnitus, though that is usually not the case.
If the otolaryngologist finds a specific cause for your tinnitus, he or she may be able to offer specific treatment to eliminate the noise. This may include removal of wax or hair from the ear canal, treatment of middle ear fluid, treatment of arthritis in the jaw joint, etc.