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 Used to Evaluate for Gallstone Disease. 1  Ultrasound â This test uses sound waves to examine the bile ducts, liver and pancreas. It is not invasive and is very safe. Stones may be seen in the gallbladder or bile ducts. Imaging may be impaired in patients who are obese or have recently eaten food.