Three in four teenagers are mobile Internet users - that is, they mostly go online using their phone and not using some other device such as a desktop or laptop computer. If a sample of 10 Hong Kong teens is selected, a) what is the probability that 4 are mobile Internet users? (7 marks) b) what is the probability that at least 2 are mobile Internet users? ( 8 marks) c) Discuss whether the four properties of binomial distribution hold in Question 1. (10 marks).