# probability of selection

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• Jan 30th 2010, 11:27 PM
netring
probability of selection
Hi guys, i am taking statistics and just wondering if im doing this right.
A system can have 3 different types of defects.
*U*=intersection

P(A)=.12 P(B)=.07 P(C)=.05
P(A U B)=.13 P(B U C)=.10 P(A U C)=.1
P(A *U* B *U* C)=.01

1. Probability system doesnt have type A defect:
1-.12=.88

2. Probability it has both A and B defects:
P(A U B)= .13

3. Probability of A and B but not C

P(A U B)-P(C)= .13 -.05=.8

4. Probability that the system has at most two of these defects?
This question im stuck on and not sure how to figure out.

Thanks guys, since im already here ill go help someone out with something i know about.
• Jan 31st 2010, 12:27 AM
CaptainBlack
Quote:

Originally Posted by netring
Hi guys, i am taking statistics and just wondering if im doing this right.
A system can have 3 different types of defects.
*U*=intersection

P(A)=.12 P(B)=.07 P(C)=.05
P(A U B)=.13 P(B U C)=.10 P(A U C)=.1
P(A *U* B *U* C)=.01

2. Probability it has both A and B defects:
P(A U B)= .13

$P(A\cap B)=P(A)+P(B)-P(A\cup B)$

CB
• Jan 31st 2010, 12:29 AM
CaptainBlack
Quote:

Originally Posted by netring
Hi guys, i am taking statistics and just wondering if im doing this right.
A system can have 3 different types of defects.
*U*=intersection

P(A)=.12 P(B)=.07 P(C)=.05
P(A U B)=.13 P(B U C)=.10 P(A U C)=.1
P(A *U* B *U* C)=.01

3. Probability of A and B but not C

P(A U B)-P(C)= .13 -.05=.8

$P(A\cap B) - P(A\cap B \cap C)$

CB
• Jan 31st 2010, 12:30 AM
CaptainBlack
Quote:

Originally Posted by netring
Hi guys, i am taking statistics and just wondering if im doing this right.
A system can have 3 different types of defects.
*U*=intersection

P(A)=.12 P(B)=.07 P(C)=.05
P(A U B)=.13 P(B U C)=.10 P(A U C)=.1
P(A *U* B *U* C)=.01

4. Probability that the system has at most two of these defects?
This question im stuck on and not sure how to figure out.

$P(A\cup B \cup C)-P(A\cap B \cap C)$

CB
• Feb 1st 2010, 11:49 AM
netring
Probability of faulty part
thanks!