# Question: The director of a local blood bank is in need

The director of a local blood bank is in need of a donor with type AB blood. The distribution of blood types for Americans is estimated by the American Red Cross to be

The director decides that if more than 20 donors are required before the first donor with AB blood appears, she will need to issue a special appeal for AB blood.

a. Conduct a simulation 10 times, using the Random Numbers applet on the text CD or a calculator or software, to estimate the probability this will happen. Show all steps of the simulation, including any assumptions that you make. Refer to Example 16 as a model for carrying out this simulation.

b. In practice, you would do at least 1000 simulations to estimate this probability well. You’d then find that the probability of exceeding 20 donors before finding a type AB donor is 0.36. Actually, simulation is not needed. Show how to find this probability using the methods of this chapter.

The director decides that if more than 20 donors are required before the first donor with AB blood appears, she will need to issue a special appeal for AB blood.

a. Conduct a simulation 10 times, using the Random Numbers applet on the text CD or a calculator or software, to estimate the probability this will happen. Show all steps of the simulation, including any assumptions that you make. Refer to Example 16 as a model for carrying out this simulation.

b. In practice, you would do at least 1000 simulations to estimate this probability well. You’d then find that the probability of exceeding 20 donors before finding a type AB donor is 0.36. Actually, simulation is not needed. Show how to find this probability using the methods of this chapter.

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