Statistics in a Modern World 800
Solutions to Exam 3
-
- .04+.29=.33
- 1-.33=.67
-
- Venn diagram overlap contains .15; in F but not U is .10; in U but not
F is .30 (outside the F and U circles is .45)
- .10+.15+.30=.55 (Alternatively, .25+.45-.15=.55)
- No, the events are not mutually exclusive because there IS overlap:
15% are first year students AND undeclared. (Many students confused being
mutually exclusive with being independent.)
- .10 are in F but not U
-
- inadmissible because probabilities can't be more than 100%
- ADMISSIBLE (don't be fooled by representativeness and the conjunction
fallacy)
- inadmissible because probabilities sum to more than 1
- inadmissible because probabilities sum to more than 1 (.3+.9=1.2)
- inadmissible because probabilities can't be negative
-
- 2/4 * 2/3 = 4/12 = 1/3
- (i) relative frequency
- 1/6 * 1/6 = 1/36
- 0(.1)+1(.1)+2(.5)+3(.3)=2
- 1/2
- gambler's fallacy
- (b)
- (d)
- (b)
- (g)
-
- (v)
- (ii)
- (e)
- (a)
- (d)
- (b)
- (b)
- (a)
-
- Not independent because there is a higher probability of having an
undeclared major for 1st year students than for others. (.6 vs. .4)
- (.25)(.6) = .15
- (.75)(.4) = .30
- .15 + .30 = .45
- .15/.45 = 1/3 or .33
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