1- Many countries governments wish to assess the proportion of the general populous that has certain deadly diseases. In many cases these diseases are rare and are thus very difficult to detect, even when screening many individuals. Thus a researcher proposes the following method of conducting infectious disease surveillance. Individuals are screened until the first infectious individual is observed, screening is then stopped and the proportion of infected individuals is estimated. If the 996th person screened, is the first person to be diagnosed as positive, suggest a method of estimating p, the true but unknown proportion of individuals who are infected, then use your method to estimate p in the context of this problem. Solution The random variable in the experiment follows a geometric distribution. -Geo(p) In a geometric distribution we get the expected value of x, E(X) by 1/(p) = E(X). Since from the experiment we know that E(X) = 996, we can put this into the formula to obtain p. -> 1/996 = p = 0.001 so, 0.1% of the population is infected..