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.
A hepatobiliary (HIDA) scan is an imaging procedure used to diagnose problems of the liver, gallbladder and bile ducts. For a HIDA scan, also known as cholescintigraphy and hepatobiliary scintigraphy, a radioactive tracer is injected into a vein in your arm.
Your ultrasound has ruled out gallstones. However, not having stones does not mean you don't have an infected gallbladder. The HIDA scan will check for this by evaluating its function. The test is simple and painless, although it can take a while. You basically just lie still for a while and let the machine do its thing.