- #1
buddingscientist
- 42
- 0
Well the first and last I'm having some troubles with, and 2-4 I think the logic I am using is correct but would like his verified since no answers were provided
What is [itex]P(A \cup B)[/itex] if [itex] P(A) = 0.2, P(A \cap B) = 0.1, P(B) = 0.5?[/itex]
Would that just be the prob. of being in A or B minus prob of being in both (prob of being in A + prob being in B - A int B). Would it depend on whether they are mutually exclusive or not? (how can we tell if that's all tahts given in the question).
I am kind of half between (A + B) and half between (A + B - AintB). But since A int B was included in the question, would that imply that I should use A + B - A int B = 0.2 + 0.5 - 0.1 = 0.6
---
What is E(X) if Mx(u) = [itex](1-u)^{-3}, u<1[/itex]
To find E(X) find the first derivative:
= -3(1-u)^(-4).-1
= 3(1-u)^(-4)
and then let u -> 0
3(1)^(-4)
=3
Therefor E(X) = 3
---
What is E([itex]X^{3}[/itex]) if fx(x) = 2x, 0<x<1
E(X^(3)) = integral (0,1) of 2x.x^3 dx
= int (0,1) 2x^4 dx
= 2/5 x^5 .. (0,1)
= 2/5
Therefor E(X^3)) = 2/5
---
What is c if
g(x) = c|x|, x = -2, -1, 1, 2 is a probability function
For it to be a prob. function, the sum of all the probabilities must equal 1
2c + c + c + 2c = 1
c = 1/6
---
What is [itex] P(\overline{B})[/itex] if [itex] P(B|\overline{A}) = 0.5, P(\overline{A}) = 0.3[/itex] [itex] and P(B|A) = 0.8 ?[/itex]
Well I'm a bit stuck on this question;
I used some multiplicative laws to find
[itex]P(A \cap B) = 0.56[/itex]
and [itex] P(B \cap \overline{A}) = 0.15 [/itex]
I'm not sure how to continue from here.
Thanks
What is [itex]P(A \cup B)[/itex] if [itex] P(A) = 0.2, P(A \cap B) = 0.1, P(B) = 0.5?[/itex]
Would that just be the prob. of being in A or B minus prob of being in both (prob of being in A + prob being in B - A int B). Would it depend on whether they are mutually exclusive or not? (how can we tell if that's all tahts given in the question).
I am kind of half between (A + B) and half between (A + B - AintB). But since A int B was included in the question, would that imply that I should use A + B - A int B = 0.2 + 0.5 - 0.1 = 0.6
---
What is E(X) if Mx(u) = [itex](1-u)^{-3}, u<1[/itex]
To find E(X) find the first derivative:
= -3(1-u)^(-4).-1
= 3(1-u)^(-4)
and then let u -> 0
3(1)^(-4)
=3
Therefor E(X) = 3
---
What is E([itex]X^{3}[/itex]) if fx(x) = 2x, 0<x<1
E(X^(3)) = integral (0,1) of 2x.x^3 dx
= int (0,1) 2x^4 dx
= 2/5 x^5 .. (0,1)
= 2/5
Therefor E(X^3)) = 2/5
---
What is c if
g(x) = c|x|, x = -2, -1, 1, 2 is a probability function
For it to be a prob. function, the sum of all the probabilities must equal 1
2c + c + c + 2c = 1
c = 1/6
---
What is [itex] P(\overline{B})[/itex] if [itex] P(B|\overline{A}) = 0.5, P(\overline{A}) = 0.3[/itex] [itex] and P(B|A) = 0.8 ?[/itex]
Well I'm a bit stuck on this question;
I used some multiplicative laws to find
[itex]P(A \cap B) = 0.56[/itex]
and [itex] P(B \cap \overline{A}) = 0.15 [/itex]
I'm not sure how to continue from here.
Thanks