Exam 1

1. Metainformation

   Tag	Value
   file	Probability_uva-addition-rule-540-en_uva-addition-rule-540-en
   name	uva-addition-rule-540-en
   section	Probability/Elementary Probability/General Rules/Addition rule
   type	schoice
   solution	FALSE, FALSE, TRUE, FALSE
   Type	Conceptual
   Language	English
   Level	Statistical Literacy
   IRT-Difficulty	2
   p-value	0.5905

   Question

   The following cross tabulation includes data from 200 individuals for two variables A and B.

   ——- ——- ——- ——- A = 1 A = 2 A = 3 B = 1 50 36 64 B = 2 20 12 18 ——- ——- ——- ——-

   The events A=2 and B=1 are

   
   
   1. FALSE: Dependent, because P(A=2 ∪ B=1) ≠ P(A=2) + P(B=1)
   2. FALSE: Dependent, because P(A=2 | B=1) P(B=1 | A=2)
   3. TRUE: Independent, because P(A=2 ∩ B=1) = P(A=2) P(B=1)
   4. FALSE: Independent, because P(A=2 ∪ B=1) = P(A=2) + P(B=1) - P(A=2 ∩ B=1)
   
   
   1. Dependent, because P(A=2 ∪ B=1) ≠ P(A=2) + P(B=1): Incorrect
   2. Dependent, because P(A=2 | B=1) P(B=1 | A=2): Incorrect
   3. Independent, because P(A=2 ∩ B=1) = P(A=2) P(B=1): Correct
   4. Independent, because P(A=2 ∪ B=1) = P(A=2) + P(B=1) - P(A=2 ∩ B=1): Incorrect