Valentin K. answered 03/10/24
Expert PhD tutor in Calculus, Statistics, and Physics
This is Binomial distribution: only two outcomes each year, 1 tornado or 0 tornadoes, and so on.
p = 0.12 (probability of "success" i.e. having a tornado that year)
n = 11 trials i.e. years.
X = number of tornadoes in 11 years
possible values of X = 0, 1, 2, 3, ....., 11
Find P(X < 3) = P(0) + P(1) + P(2), which will be your answer.
You can use any Binomial calculator or calculate each term by hand, using formulas, and add them up.