SOLUTION: Assume the random variable X has a binomial distribution with the given probability of obtaining a success. Find the following probability, given the number of trials and the proba

The general formula to calculate the binomial cumulative probability (n trials; success trials from 0 to k; probability of success p) is


     P(n; i <= k; p) = ,


where   =  are binomial coefficients.



In your case, the number of trials is n= 3; success trials are at i= 0,1 (k=1); p = 0.8.  The formula takes the form


     P(n=3; i <= 1; p=0.8) =  =  +  = 

                          = 1*1*0.2^3 + 3*0.8*0.2^2 = use your calculator = 0.104.   ANSWER


ANSWER.  The resulting probability is P = 0.104.