Joint Probability of Non-Independent Events
For the joint probability of non-independent events A and B, we need to use a conditional probability.
For P(Zargon-AND-Abduct), we cab use P(Zargon|Abduct) or P(Abduct|Zargon).
P(Zargon) x P(Abduct|Zargon) = 8
/20 x 3
/8 = 24/160 = 3
/20
P(Abduct) x P(Zargon|Abduct) = 6
/20 x 3
/6 = 18/120 = 3
/20
Here is a different problem. The UFOs are invading, and the military shoots two special UFO missiles.
The missiles blow up two of the UFOs. What is P(1stZargon-AND-2ndZargon)?
Destroying a Zargon UFO with the second missile is not independent of the preceding events. When the first missile destroys a UFO, the total number of UFOs decreases from 20 to 19. And if it hits a
Zargon UFO, the number of Zargon UFOs decreases from 8 to 7. …show more content…
Conjunction Rule
P(A) x P(B|A) = P(A-AND-B) = P(B) x P(A|B)
The rule is general; it always works. If A and B are independent, then P(B|A) = P(B), and the answer will be the same as P(A) x P(B).
© Lyle Crawford - 177 -
A Common Confusion
Joint probability and conditional probability are completely different things.
Joint Probability Conditional Probability …show more content…
We are in a car, stuck in a huge traffic jam. There are cars lined up all the way down the road, and there are big orange signs, flashing lights, and traffic cones along the road. Which is more probable?
Statement 9.5: The next prime minister of Canada will
For the joint probability of non-independent events A and B, we need to use a conditional probability.
For P(Zargon-AND-Abduct), we cab use P(Zargon|Abduct) or P(Abduct|Zargon).
P(Zargon) x P(Abduct|Zargon) = 8
/20 x 3
/8 = 24/160 = 3
/20
P(Abduct) x P(Zargon|Abduct) = 6
/20 x 3
/6 = 18/120 = 3
/20
Here is a different problem. The UFOs are invading, and the military shoots two special UFO missiles.
The missiles blow up two of the UFOs. What is P(1stZargon-AND-2ndZargon)?
Destroying a Zargon UFO with the second missile is not independent of the preceding events. When the first missile destroys a UFO, the total number of UFOs decreases from 20 to 19. And if it hits a
Zargon UFO, the number of Zargon UFOs decreases from 8 to 7. …show more content…
Conjunction Rule
P(A) x P(B|A) = P(A-AND-B) = P(B) x P(A|B)
The rule is general; it always works. If A and B are independent, then P(B|A) = P(B), and the answer will be the same as P(A) x P(B).
© Lyle Crawford - 177 -
A Common Confusion
Joint probability and conditional probability are completely different things.
Joint Probability Conditional Probability …show more content…
We are in a car, stuck in a huge traffic jam. There are cars lined up all the way down the road, and there are big orange signs, flashing lights, and traffic cones along the road. Which is more probable?
Statement 9.5: The next prime minister of Canada will