Solve the problem.
-On a multiple choice test with 11 questions, each question has four possible answers, one of which is correct. For students who guess at all answers, find the standard deviation for the number of correct answers.
A)1.407
B)1.342
C)1.369
D)1.436

Question

Quizplus · Accepted Answer

The standard deviation for a binomial distribution is given by the formula $\sqrt{n \cdot p \cdot (1-p)}$, where $n$ is the number of trials (in this case, 11 questions), and $p$ is the probability of success on each trial (since there is one correct answer out of four choices, $p = 0.25$). Plugging these values in, we get $\sqrt{11 \cdot 0.25 \cdot (1-0.25)} = \sqrt{11 \cdot 0.25 \cdot 0.75} = \sqrt{2.0625} \approx 1.436$.

Solve the Problem. -On a Multiple Choice Test with 11 Questions, Each Question