SOLUTION: The final exam in a sociology course consists of 100 multiple-choice questions. Each question has five possible answers, and only one of them is correct. An unprepared student make

Algebra ->  Probability-and-statistics -> SOLUTION: The final exam in a sociology course consists of 100 multiple-choice questions. Each question has five possible answers, and only one of them is correct. An unprepared student make      Log On


   

Question 884420: The final exam in a sociology course consists of 100 multiple-choice questions. Each question has five possible answers, and only one of them is correct. An unprepared student makes random guesses for all of the answers.
Find the mean and standard deviation for the number of correct answers for such students.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The final exam in a sociology course consists of 100 multiple-choice questions. Each question has five possible answers, and only one of them is correct. An unprepared student makes random guesses for all of the answers.
Find the mean and standard deviation for the number of correct answers for such students.
------------------
mean = np = 100(1/5) = 20
std = sqrt(npq) = sqrt(20(4/5)) = sqrt(16) = 4
-----------------------
Cheers,
Stan H.
------------------