Exercise 4. (8p) In this exercise we consider the Bienaymé Galton Watson processes (Z_(n)) with p_(0) = (7)/(10), p_(3) = (2)/(10), p_(10) = (9)/(100), p_(50) = (1)/(100). For example, Covid (SARS-CoV-2) was roughly similar to this in 2020-2021: people had a high probability p_(0) to contaminate no one, but also a not-so-small probability to contaminate many people (a small number of people contributed to a significant proportion of the contaminations).
(a) (2p) What is G_(1) in this case?
(b) (2p) Compute μ and σ.
(c) (4p) Make a drawing representing the graph of G_(1) and the first diagonal "y=x". Indicate on the drawing how to find η and use a calculator to find an approximation of η. (Give 2 characteristic digits, for example writing the result as η = 4.5*10^(-1) or 8.2*10^(-2)).