|
Correct answer is B
A is incorrect. 0.2350 = (0.9*0.05 + 0.2 * 0.95).
B is correct. Let A be the event of default and B be the event of a significant drop in stock price. By Bayes' Theorem, P(A|B) = P(B|A) * P(A) / (P(B|A) * P(A) + P(B|not A) * P(not A)). So, for the data provided,
P(A|B) = (0.05*0.90)/(0.05*0.90+0.95*0.20) = 0.1915
C is incorrect. 0.2368 = 0.9*0.05 / (0.2 * 0.95).
D is incorrect. 0.0450 = 0.9*0.05.
Reference: Murray R. Spiegel, John Schiller, and R. Alu Srinivasan, Probability and Statistics, Schaum's Outlines, 2nd ed. (New York: McGraw-Hill, 2000), Chapter 1.
Type of Question: Quantitative Analysis | 
发表于 2009-6-13 10:07
| 