The Red Cross needs blood donors with blood type O-negative. It is reported that only 7.2% of the US population has blood type O-negative, and that 9.2 million people in the US were blood donors in 2013.
a) How many of those donors should the Red Cross have expected to have type O-negative blood?
b) A typical donation is one pint, so assuming the typical donation and that each person only donates once, what amount of O-negative blood could the Red Cross have expected? Is this a minimum or maximum and why?
c) What is the probability that a site that collects 1000 donations gets at least 2 pints of O-negative blood?