Question

A 10-question multiple choice test has 4 possible answers
for each question. A student guesses on all ten answer.
a)What is the probability that the student selects at least 6 correct answers?
b)Is getting exactly 10 questions correct the same probability as getting exactly zero correct?
c)Describe the steps needed to calculate the probability of getting at least six questions correct if the student randomly guesses. You do not need to calculate this probability.

Pleaaaasssee heeelppp I am super stuck and don't know how to answer this question!!!!!

Answer 1

How does a differ from c?

If the events are independent, the probability of both/all events occurring is determined by multiplying the probabilities of the individual events.

b) (3/4)^20

c) "at least 6" translates to either 6, 7, 8, 9 or 10.

Either-or probabilities are found by adding the individual probabilities.

P(correct) = 1/4

P(incorrect) = 3/4

p(6 correct) = (1/4)^6 * (3/4)^4

Calculate for 7, 8, 9, and 10, then add.

Answer 2

4/4096