- CFA Exams
- 2021 CFA Level I Exam
- Study Session 3. Quantitative Methods (2)
- Reading 9. Common Probability Distributions
- Subject 5. The Binomial Distribution

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**CFA Practice Question**

There are five multiple-choice questions on an exam, each having responses a, b, c, or d. Each question is worth 5 points and only one option per question is correct. Suppose a student guesses the answer to each question, and his or her guesses from question to question are independent. The student's mean number of questions correct on the exam should be ______.

B. 2.5

C. 6.25

A. 1.25

B. 2.5

C. 6.25

Correct Answer: A

X, the number correct if you were guessing, has the binomial distribution with parameters n = 5 and p = 0.25. The mean of X is u = np = 1.25.

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**User Contributed Comments**
2

User |
Comment |
---|---|

TammTamm |
Another easy guess. 5/4=1.25. |

lawlee |
why won't it be 1? |