Is $P(E/bar F) + P(bar E/ bar F) = 1$?
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1
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Is $P(E/bar F) + P(bar E/ bar F) = 1$?
I tried using venn diagram and here's what I get:
The red region shows $P(E/ bar F)$ and the blue region shows $P(bar E/ bar F)$
Clearly it is not $1$ but my book says it is. Where have I misunderstood?
probability
add a comment |
up vote
1
down vote
favorite
Is $P(E/bar F) + P(bar E/ bar F) = 1$?
I tried using venn diagram and here's what I get:
The red region shows $P(E/ bar F)$ and the blue region shows $P(bar E/ bar F)$
Clearly it is not $1$ but my book says it is. Where have I misunderstood?
probability
You probably confuse the relative complement and the conditional probability.
– Hanul Jeon
2 days ago
You are confusing $/$ , that is conditional probability, with $cap$, the intersection. Conditional probability $P(E / F)$ requires that you take the ratio $frac{P(E cap F)}{P(F)}$, so it is not the probability of some event in the space, but rather a ratio of two probabilities, which can't be represented on the Venn diagram.
– астон вілла олоф мэллбэрг
2 days ago
Is $P(E/F)$ a conditional probability. If so, then recall the definition of conditional probability.
– Lord Shark the Unknown
2 days ago
Is it not possible to sketch conditional probability on venn diagram @LordSharktheUnknown
– Abcd
2 days ago
@Abcd You can sketch it. Just cut out the circle for $F$. Now, this is your new sample space.
– trancelocation
2 days ago
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
Is $P(E/bar F) + P(bar E/ bar F) = 1$?
I tried using venn diagram and here's what I get:
The red region shows $P(E/ bar F)$ and the blue region shows $P(bar E/ bar F)$
Clearly it is not $1$ but my book says it is. Where have I misunderstood?
probability
Is $P(E/bar F) + P(bar E/ bar F) = 1$?
I tried using venn diagram and here's what I get:
The red region shows $P(E/ bar F)$ and the blue region shows $P(bar E/ bar F)$
Clearly it is not $1$ but my book says it is. Where have I misunderstood?
probability
probability
asked 2 days ago
Abcd
2,87311130
2,87311130
You probably confuse the relative complement and the conditional probability.
– Hanul Jeon
2 days ago
You are confusing $/$ , that is conditional probability, with $cap$, the intersection. Conditional probability $P(E / F)$ requires that you take the ratio $frac{P(E cap F)}{P(F)}$, so it is not the probability of some event in the space, but rather a ratio of two probabilities, which can't be represented on the Venn diagram.
– астон вілла олоф мэллбэрг
2 days ago
Is $P(E/F)$ a conditional probability. If so, then recall the definition of conditional probability.
– Lord Shark the Unknown
2 days ago
Is it not possible to sketch conditional probability on venn diagram @LordSharktheUnknown
– Abcd
2 days ago
@Abcd You can sketch it. Just cut out the circle for $F$. Now, this is your new sample space.
– trancelocation
2 days ago
add a comment |
You probably confuse the relative complement and the conditional probability.
– Hanul Jeon
2 days ago
You are confusing $/$ , that is conditional probability, with $cap$, the intersection. Conditional probability $P(E / F)$ requires that you take the ratio $frac{P(E cap F)}{P(F)}$, so it is not the probability of some event in the space, but rather a ratio of two probabilities, which can't be represented on the Venn diagram.
– астон вілла олоф мэллбэрг
2 days ago
Is $P(E/F)$ a conditional probability. If so, then recall the definition of conditional probability.
– Lord Shark the Unknown
2 days ago
Is it not possible to sketch conditional probability on venn diagram @LordSharktheUnknown
– Abcd
2 days ago
@Abcd You can sketch it. Just cut out the circle for $F$. Now, this is your new sample space.
– trancelocation
2 days ago
You probably confuse the relative complement and the conditional probability.
– Hanul Jeon
2 days ago
You probably confuse the relative complement and the conditional probability.
– Hanul Jeon
2 days ago
You are confusing $/$ , that is conditional probability, with $cap$, the intersection. Conditional probability $P(E / F)$ requires that you take the ratio $frac{P(E cap F)}{P(F)}$, so it is not the probability of some event in the space, but rather a ratio of two probabilities, which can't be represented on the Venn diagram.
– астон вілла олоф мэллбэрг
2 days ago
You are confusing $/$ , that is conditional probability, with $cap$, the intersection. Conditional probability $P(E / F)$ requires that you take the ratio $frac{P(E cap F)}{P(F)}$, so it is not the probability of some event in the space, but rather a ratio of two probabilities, which can't be represented on the Venn diagram.
– астон вілла олоф мэллбэрг
2 days ago
Is $P(E/F)$ a conditional probability. If so, then recall the definition of conditional probability.
– Lord Shark the Unknown
2 days ago
Is $P(E/F)$ a conditional probability. If so, then recall the definition of conditional probability.
– Lord Shark the Unknown
2 days ago
Is it not possible to sketch conditional probability on venn diagram @LordSharktheUnknown
– Abcd
2 days ago
Is it not possible to sketch conditional probability on venn diagram @LordSharktheUnknown
– Abcd
2 days ago
@Abcd You can sketch it. Just cut out the circle for $F$. Now, this is your new sample space.
– trancelocation
2 days ago
@Abcd You can sketch it. Just cut out the circle for $F$. Now, this is your new sample space.
– trancelocation
2 days ago
add a comment |
2 Answers
2
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up vote
0
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Note that
$(E cap bar F) cup (bar E cap bar F) = bar F$ and- $(E cap bar F) cap (bar E cap bar F) = emptyset$
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Since $E$ and $bar{E}$ are disjoint events we have:
$$mathbb{P}(E|bar{F}) + mathbb{P}(bar{E}|bar{F}) = mathbb{P}(E cup bar{E}|bar{F}) = mathbb{P}(Omega|bar{F}) = 1.$$
The first step follows from the additivity axiom of probability and the last follows from the norming axiom. Your diagram does not accurately show the conditional probabilities: the first is the relative size of the red area in the union of both the red and blue areas, and the second is the relative size of the blue area in the union of both the red and blue areas, which sum to the whole area (i.e., one).
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
Note that
$(E cap bar F) cup (bar E cap bar F) = bar F$ and- $(E cap bar F) cap (bar E cap bar F) = emptyset$
add a comment |
up vote
0
down vote
Note that
$(E cap bar F) cup (bar E cap bar F) = bar F$ and- $(E cap bar F) cap (bar E cap bar F) = emptyset$
add a comment |
up vote
0
down vote
up vote
0
down vote
Note that
$(E cap bar F) cup (bar E cap bar F) = bar F$ and- $(E cap bar F) cap (bar E cap bar F) = emptyset$
Note that
$(E cap bar F) cup (bar E cap bar F) = bar F$ and- $(E cap bar F) cap (bar E cap bar F) = emptyset$
answered 2 days ago
trancelocation
7,8461519
7,8461519
add a comment |
add a comment |
up vote
0
down vote
Since $E$ and $bar{E}$ are disjoint events we have:
$$mathbb{P}(E|bar{F}) + mathbb{P}(bar{E}|bar{F}) = mathbb{P}(E cup bar{E}|bar{F}) = mathbb{P}(Omega|bar{F}) = 1.$$
The first step follows from the additivity axiom of probability and the last follows from the norming axiom. Your diagram does not accurately show the conditional probabilities: the first is the relative size of the red area in the union of both the red and blue areas, and the second is the relative size of the blue area in the union of both the red and blue areas, which sum to the whole area (i.e., one).
add a comment |
up vote
0
down vote
Since $E$ and $bar{E}$ are disjoint events we have:
$$mathbb{P}(E|bar{F}) + mathbb{P}(bar{E}|bar{F}) = mathbb{P}(E cup bar{E}|bar{F}) = mathbb{P}(Omega|bar{F}) = 1.$$
The first step follows from the additivity axiom of probability and the last follows from the norming axiom. Your diagram does not accurately show the conditional probabilities: the first is the relative size of the red area in the union of both the red and blue areas, and the second is the relative size of the blue area in the union of both the red and blue areas, which sum to the whole area (i.e., one).
add a comment |
up vote
0
down vote
up vote
0
down vote
Since $E$ and $bar{E}$ are disjoint events we have:
$$mathbb{P}(E|bar{F}) + mathbb{P}(bar{E}|bar{F}) = mathbb{P}(E cup bar{E}|bar{F}) = mathbb{P}(Omega|bar{F}) = 1.$$
The first step follows from the additivity axiom of probability and the last follows from the norming axiom. Your diagram does not accurately show the conditional probabilities: the first is the relative size of the red area in the union of both the red and blue areas, and the second is the relative size of the blue area in the union of both the red and blue areas, which sum to the whole area (i.e., one).
Since $E$ and $bar{E}$ are disjoint events we have:
$$mathbb{P}(E|bar{F}) + mathbb{P}(bar{E}|bar{F}) = mathbb{P}(E cup bar{E}|bar{F}) = mathbb{P}(Omega|bar{F}) = 1.$$
The first step follows from the additivity axiom of probability and the last follows from the norming axiom. Your diagram does not accurately show the conditional probabilities: the first is the relative size of the red area in the union of both the red and blue areas, and the second is the relative size of the blue area in the union of both the red and blue areas, which sum to the whole area (i.e., one).
answered 2 days ago
Ben
87311
87311
add a comment |
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You probably confuse the relative complement and the conditional probability.
– Hanul Jeon
2 days ago
You are confusing $/$ , that is conditional probability, with $cap$, the intersection. Conditional probability $P(E / F)$ requires that you take the ratio $frac{P(E cap F)}{P(F)}$, so it is not the probability of some event in the space, but rather a ratio of two probabilities, which can't be represented on the Venn diagram.
– астон вілла олоф мэллбэрг
2 days ago
Is $P(E/F)$ a conditional probability. If so, then recall the definition of conditional probability.
– Lord Shark the Unknown
2 days ago
Is it not possible to sketch conditional probability on venn diagram @LordSharktheUnknown
– Abcd
2 days ago
@Abcd You can sketch it. Just cut out the circle for $F$. Now, this is your new sample space.
– trancelocation
2 days ago