CISC 7700X Midterm Exam

1. d. Via contraposition, this statement is equivalent to: If something is not in water, then it is not a fish. https://en.wikipedia.org/wiki/Raven_paradox, 
2. d
3. Without vaccine, a lot more people would die from smallpox.
4. c
5. b
6. b  e.g. return after 3 years: (1+0.35)*(1+0.35)*(1-0.70)=0.54675 (or 54%). geometric mean: ((1+0.35)*(1+0.35)*(1-0.70))^(1/3)=0.81770. return after 3 years using mean: 0.81770^3=0.54674
7. d
8. d
9. e. invalid.
10. a
11. c
12. d: ~7. sqrt(2*5*5).
13. a
14. b
15. e; 8/17 or 0.47059 
   P(default) = 1/10, P(-default) = 9/10, P(mustache|default) = 8/10, P(-mustache|default) = 2/10, P(mustache|-default) = 1/10, P(-mustache|-default) = 9/10
   P(default|mustache) = P(mustache|default)*P(default) / (P(mustache|-default)*P(-default)+P(mustache|default)*P(default)) = 
      ((8/10) * (1/10)) / ( (8/10) * (1/10) + (1/10)*(9/10)) = 8/100 / (8/100 + 9/100) = 8/100 / (17/100) = 8/17 = 0.47059
16. c
17. a
18. b
19. c
20. d