Success is the desired or the favorable outcome of an event.
A.1/6
B. 1/4
C.1/8
D. 1/2
Correct Answer: D
Step 1: In a single trial, probability p of success is given by p = P (getting a head) =1/2 .
Step 2: Probability of failure, q = 1 - p = 1 -1/2 = 1/2.
Step 3:
[Binomial distribution.]
Step 4: P(r) = p(3) + p(4) + p(5)
Step 5:
Step 6:
Step 7: 
Q1: A die is rolled 3 times. Getting a 4 is considered a success. What is the probability of exactly 2 successes?
Q: What does 'at least' mean in probability?
A: It means the probability of that value or higher values. For example, 'at least 3' means 3, 4, 5, etc.