A medical research team wishes to evaluate a proposed screening test for Hepatitis B. It is known that 2.5% of the population has Hepatitis B. The test was given to a random sample of 300 patients with Hepatitis B and an independent random sample of 400 patients without Hepatitis B. Among the patients with Hepatitis B, 273 resulted positive. Among the patients without Hepatitis B, 40 resulted positive.
1. What is the specificity of this screening test? Interpret it in the context of the problem.
2. Explain what a false negative represents in the context of this screening test and determine its probability.
3. Compute the predicted value negative (P.V.N.) for this screening test and interpret it in the context of the problem.