SOLUTION: The weather forcaster has predicted that there is a 25% probability of rain on any of the next 4 days. What is the probability that it will rain at least twice?

 

Hi

p(rain) = .25, n = 4

P(x >= 2) = 1 - binomcdf(4, .25, 1) = .2617  (Recommend Using TI)

Or P(x >= 2) = P(2) + P(3) + P(4)

Using 

 

p and q are the probabilities of success and failure respectively. 

In this case p= .25, q = .75,  n=4