Probability is simply how likely something is to happen. Whenever we’re unsure about the outcome of an event, we can talk about the probabilities of certain things to happen.

In a binomial probability (p);

- The number of trials (n) are fixed.
- Ther only two possible outcmes; a success (k) or a failure (q).

**Formula to calculate binomial probability.**

To calculate probability, we take n combination k and multiply it by p power k and q power (n – k).

**Example:**

You are taking a 5 question multiple choice test. If each question has four choices and you guess on each question, what is the probability of getting exactly 3 questions correct?

Number of trials (n) = 5

Success (k) = 3

Probability of getting the correct answer 0.25.

Probability of getting the wrong answer 0.75.

Therefore, the probability of getting exactly 3 questions is 0.08.