Step 1 :We are given a problem where random guesses are made for 8 multiple-choice questions on a test with 5 choices for each question. We are asked to find the probability of no correct answers.
Step 2 :This is a binomial distribution problem. The binomial distribution model deals with finding the probability of success of an event which has only two possible outcomes in a series of experiments.
Step 3 :For a random variable X if X is B(n, p) where n is the number of trials, and p is the probability of success on each trial, we can find the probability of getting exactly k successes among n trials is given by the function: \(P(X=k) = C(n, k) * (p^k) * (1-p)^(n-k)\) where C(n, k) is the binomial coefficient.
Step 4 :In this case, we are looking for the probability of no correct answers, which means k=0. So we can substitute n=8, p=0.20 and k=0 into the formula and calculate the result.
Step 5 :Substituting the given values into the formula, we get \(P(X=0) = C(8, 0) * (0.2^0) * (1-0.2)^(8-0)\)
Step 6 :Solving the above expression, we get \(P = 0.1677721600000001\)
Step 7 :Rounding to three decimal places as needed, we get \(P = 0.168\)
Step 8 :Final Answer: The probability of no correct answers is \(\boxed{0.168}\)