- CFA Exams
- CFA Level I Exam
- Study Session 3. Quantitative Methods (2)
- Reading 9. Common Probability Distributions
- Subject 1. Basic Definitions

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**CFA Practice Question**

Suppose you have a discrete probability function such that P(X=5) = 10%, P(X=6) = 20%, P(X=7) = 30%, P(X=8) = 20%, P(X=9) = 20%. Find F(8).

A. 20%

B. 60%

C. 80%

**Explanation:**F(8) is the probability that the function takes on values less than or equal to 8. So, F(8) = p(5) + p(6) + p(7) + p(8) = 0.10 + 0.20 + 0.30 + 0.20 = 0.80 = 80%.

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**User Contributed Comments**
2

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

Mariecfa |
Total of all probabilities equals one. Since we don't need P(x=9) we can subtract .20 from 1 with out having to all the first eight probabilities. |

Patdotcom |
Where did it say that it was a cummulative function? F(x) shouldn´t it be in this case F(X=x)? |