Suppose that a quiz consists of 20 true-false questions. A student has not studied for the exam and just randomly guesses the answers. How would you find the probability that the student will get 8 or fewer answers correct?
A. Find the probability that X = 8 in a binomial distribution with n=20 and p = 0.5.
B. Find the area between 0 and 8 in a uniform distribution that goes from 0 to 20.
C. Find the probability that X = 8 for a normal distribution with mean of 10 and standard deviation of 5.
D. Find the cumulative probability for 8 in a binomial distribution with n = 20 and p=0.5.
Answer:D
A binomial distribution is a probability distribution, and it refers to the various probabilities associated with the number of correct answers out of the total sample. The correct approach is to find the cumulative probability for 8 in a binomial distribution with N = 20 and p=0.5. The cumulative probability is to be calculated on the basis of a binomial distribution with number of questions (n) equaling 20 and probability of a single event occurring being 50% (p = 0.5).

 
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