1 (If you don't know what these, are set them each to 0.5. 2  z is the value that specifies the level of confidence you want in your confidence interval when you analyze your data. 3  Typical levels of confidence for surveys are 95%, in which case z is set to 1.96. 4  E sets the accuracy of your sample proportions.
Tests and diagnosis discussion for Gallstones: Many gallstones, especially silent stones, are discovered by accident during tests for other problems. But when gallstones are suspected to be the cause of symptoms, the doctor is likely to do an ultrasound exam. Ultrasound uses sound waves to create images of organs.
Tests to diagnose kidney stones. Your doctor may do one or more of the following tests to help diagnose kidney stones, see where they are located, and find out if they are causing or may cause damage to the urinary tract . A noncontrast spiral computed tomography (CT) scan is the preferred test for kidney stones.