Given:
n = 13, the number of questions
p = 1/4, probability of guessing a correct answer among 4 choices.
q = 3/4, probability of guessing an incorrect answer (q = 1 -p).
The problem is modeled by a binomial distribution.
The mean value is μ = np.
The standard deviation is √(npq).
For the given problem, the standard deviation is
√(13*(1/4)*(3/4)) = 1.561
Answer: 1.56 (nearest hunderdth)
