SOLUTION: There are twenty multiple choice questions in an exam. Each question has four possible answers, and only one of them is correct. How can we find the probability of having 15 or mor
Algebra.Com
Question 1104196: There are twenty multiple choice questions in an exam. Each question has four possible answers, and only one of them is correct. How can we find the probability of having 15 or more correct answers if a student attempts to answer every question at random. And last thing, how can we find the probability of having 5 or less correct answers? Regards...
Answer by rothauserc(4718) (Show Source): You can put this solution on YOUR website!
use the binomial probability formula
:
Probability (P) ( k successes in n trials) = nCk * p^k * (1-p)^(n-k), where nCk = n! / (k! * (n - k)!)
:
for this problem p = 0.25 (probability of guessing a correct answer given 4 choices)
:
P ( 15 or more correct out of 20 ) = P (15 correct out of 20) + P (16 correct out of 20) + P (17 correct out of 20) + P (18 correct out of 20) + P (19 correct out of 20) + P (20 correct out of 20) = 3.8E06
:
P ( 5 or less correct out of 20 ) = P (5 correct out of 20) + P (4 correct out of 20) + P (3 correct out of 20) + P (2 correct out of 20) + P (1 correct out of 20) + P (0 correct out of 20) = 0.617 approximately 0.62
:
RELATED QUESTIONS
The final exam in a sociology course consists of 100 multiple-choice questions. Each... (answered by stanbon)
Each question of a five-question multiple choice exam has four possible answers. Whitney... (answered by stanbon)
There are five multiple-choice questions on an exam, each with four possible answers.... (answered by reviewermath)
I cant find the correct answers to these questions. Please help!
A test consists of... (answered by ewatrrr)
Part I of the exam has a seven question multiple-choice questions. If each question has... (answered by TimothyLamb)
There are 6 multiple-choice questions on an exam, each with four possible answers. Only... (answered by stanbon)
A student is taking a multiple-choice exam in which each question has four choices.... (answered by ikleyn)
John is taking an exam, but hasn’t studied or gone to class all term. He figures on... (answered by richwmiller,stanbon)
A student is taking a multiple-choice exam in which each equation has four choices.... (answered by ikleyn)