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.
gallstone. a stonelike mass (calculus) in the gallbladder; the presence of gallstones is known medically as cholelithiasis. The cause is unknown, although there is evidence of a connection between gallstones and obesity; an excess of cholesterol in the bile appears to be of major importance.Gallstones are most common in women after pregnancy, and in both men and women past age 35.They may be present for years without causing trouble.he cause is unknown, although there is evidence of a connection between gallstones and obesity; an excess of cholesterol in the bile appears to be of major importance. Gallstones are most common in women after pregnancy, and in both men and women past age 35. They may be present for years without causing trouble.