remember that and .
let x be a random variable that follows a binomial distribution with parameters n=20 and p=2/3 (i.e.X~Bin (20,2/3)
What is the probability that X takes the value 13?
Compute the exception, E(X), and variance, var(X), of X
Also another question giving me trouble is:
A die is rolled successively until a 6 comes up. How many rolls are necessary before the probability is at least 1/2 that the 6 will turn up at least once? What probability definition are you using? Indicate what probability rules you are using (if any).
WOULD BE REALLY GRATEFUL IF SOMEONE COULD POST THE ANSWERS TO THESE QUESTIONS!!!!