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Statistics probability question?
x | P(x)
-5 | 0.05
10 | 0.05
50 | 0.40
100 | 0.50
Considering the above discrete probability distribution table, find P( X > 21 | X < 60).
Now I know I should be using the conditional probability formula P(A|B) = P(A n B)/P(B), but I haven't dealt with a situation where A and B are in this "X > 21" form.
Any help greatly appreciated.
1 Answer
- SkepticLv 71 decade agoFavorite Answer
The given fact that x < 60 eliminates the 100 outcome only. You start with:
x | P(x)
-5 | 0.05
10 | 0.05
50 | 0.40
100 | 0.50 <== Eliminate this outcome
An now the probabilities are .05/.5; .05/.5; and .40/.5.
x | P(x)
-5 | 0.05/.5 = .10
10 | 0.05/.5 = .10
50 | 0.40/.5 = .80
You are looking for x>21 which occurs when x=50. The probability is .80 and you didn't even need to use any formulas. You should focus on understanding the problem rather than trying to force a formula into the solution.
