Suppose that one in every 100 people in a certain community is infected with HIV. You want to indentify an HIV-positive person to include inn a study of an experimental new drug. How many indiviuals would you expect to have to interview in order to find the first person who is HIV-positive?
To find out how many individuals you would expect to interview in order to find the first person who is HIV-positive, you need to calculate the expected number of trials.
Here's how you can do it:
1. Convert the probability of success (P) into a decimal. In this case, the probability of selecting an HIV-positive person is 1 in 100, which can be written as 0.01.
2. Calculate the expected number of trials (E) using the formula: E = 1/P. In this case, E = 1/0.01 = 100.
Therefore, you would expect to interview approximately 100 individuals in order to find the first person who is HIV-positive.