Answer:
8.81% probability that the student answers exactly 4 questions correctly
Step-by-step explanation:
For each question, there are only two possible outcomes. Either he answers it correctly, or he does not. The probability of answering a question correctly is independent of other questions. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which is the number of different combinations of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
A multiple choice exam has ten questions.
This means that
The probability of answering any question correctly is 0.20.
This means that
What is the probability that the student answers exactly 4 questions correctly
This is P(X = 4).
8.81% probability that the student answers exactly 4 questions correctly