Question

Assume that random guesses are made for eight multiple choice questions on an SAT​ test, so that there are nequals8 ​trials, each with probability of success​ (correct) given by pequals0.3. Find the indicated probability for the number of correct answers. Find the probability that the number x of correct answers is fewer than 4.

Answer 1

The given random variable X (number of correct answer) is a binomila random variable with given number of trails and probability of success , then the formula for calculating the probability of observing exactly x successes in n trials is given by-

We are asked to find the probability that and it is calculated as-

So the probability that the number of correct answer is fewer than 4 is calculated as 0.8059