# Tree Diagram Help

• Apr 24th 2007, 02:25 AM
omrkwlh
Tree Diagram Help
Hi hows it going guys. I have some problem with tree diagram.

A manufacturer of metal bolts uses an X-ray scanner to reject bolts which have defects. In a review of the scanner’s reliability, 750 bolts were checked by the scanner and then by an accurate human inspector. The table shows the number of bolts accepted or rejected by the scanner and whether the bolts were, in fact, defective or OK.
In this question, the following notation should be used.
A: the casting was accepted by the scanner
D: the casting was defective Scanner

(a)Draw a tree diagram and label its branches to show the sample space of this problem.

(b)On the basis of these results, calculate the probability correct to 4 decimal places, that a randomly selected bolt
(i)is defective and is accepted by the scanner
(ii)is accepted by the scanner
(iii)will be accepted by the scanner if it is defective

many thanks
• Apr 24th 2007, 07:07 AM
Glaysher
• Apr 24th 2007, 07:09 AM
Glaysher
Quote:

Originally Posted by omrkwlh
(b)On the basis of these results, calculate the probability correct to 4 decimal places, that a randomly selected bolt
(i)is defective and is accepted by the scanner
(ii)is accepted by the scanner
(iii)will be accepted by the scanner if it is defective

many thanks

i) 12/750 =

ii) 734/750 =

iii) 12/18 =
• Apr 24th 2007, 12:39 PM
CaptainBlack
Quote:

Originally Posted by Glaysher

Corrected diagram in attachment
• Apr 24th 2007, 11:22 PM
Glaysher
Quote:

Originally Posted by CaptainBlack
Corrected diagram in attachment

Stupid typo. Thanks
• Apr 25th 2007, 11:00 PM
omrkwlh
those 2 events A and D are they considered as mutually exclusive or independent?
• Apr 26th 2007, 01:02 AM
Glaysher
Quote:

Originally Posted by omrkwlh
those 2 events A and D are they considered as mutually exclusive or independent?

Mutually exclusive means they can't happen together ie probability of A and D happening together is zero

Independent means the probability of A and D happening together is the same as the probability of A happening multiplied by the probability of D happening
• Apr 26th 2007, 03:28 PM
omrkwlh
err still dont get it mate