A simple logic problem

[festeringZit]

Come on you 50%ers talking like you know for sure.

I will bet any amount of money that the answer is 2/3.

This is a betting forum, bring it on.

 

[viking611]

http://en.wikipedia.org/wiki/Boy_or_Girl_paradox

 

[Illini]

a=boy or girl
b=boy or girl

a=boy

What is the probability that b is a boy?
-Same as it always was

What is the probability that b is a girl?
-Same as it always was

a=boy so what? Doesn't answer a damn thing about b.

 

[Illini]

Come on you 50%ers talking like you know for sure.

I will bet any amount of money that the answer is 2/3.

This is a betting forum, bring it on.

I've explained why I'm right and you're wrong.

It seems that no matter how I spell it out, you aren't going to agree.

 

[GoForBroke]

come on you 50%ers talking like you know for sure.

I will bet any amount of money that the answer is 2/3.

This is a betting forum, bring it on.

 

[viking611]

Suppose you have three cards:

• a black card that is black on both sides,
• a white card that is white on both sides, and
• a mixed card that is black on one side and white on the other.

You put all of the cards in a hat, pull one out at random, and place it on a table. The side facing up is black. What are the odds that the other side is also black?
The answer is that the other side is black with probability 2/3. However, common intuition suggests a probability of 1/2 because across all the cards, there are 3 white, 3 black. However, many people forget to eliminate the possibility of the "white card" in this situation (i.e. the card they flipped CANNOT be the "white card" because a black side was turned over).
In a survey of 53 Psychology freshmen taking an introductory probability course, 35 incorrectly responded 1/2; only 3 students correctly responded 2/3.

 

[Geoff101]

Come on you 50%ers talking like you know for sure.

I will bet any amount of money that the answer is 2/3.

This is a betting forum, bring it on.

I told you I am willing to drive down and put your logic to the test....are you taking me up on it or not?????
you are wrong and i think the only way to prove it to you is to consistently take your money...which im willing to do....do you want to come up to fort worth this weekend instead....i can meet you here this weekend and we can put your math to the test.

 

[Illini]

Suppose you have three cards:

• a black card that is black on both sides,
• a white card that is white on both sides, and
• a mixed card that is black on one side and white on the other.

You put all of the cards in a hat, pull one out at random, and place it on a table. The side facing up is black. What are the odds that the other side is also black?
The answer is that the other side is black with probability 2/3. However, common intuition suggests a probability of 1/2 because across all the cards, there are 3 white, 3 black. However, many people forget to eliminate the possibility of the "white card" in this situation (i.e. the card they flipped CANNOT be the "white card" because a black side was turned over).
In a survey of 53 Psychology freshmen taking an introductory probability course, 35 incorrectly responded 1/2; only 3 students correctly responded 2/3.

It's not the same problem as this one.

For this problem, the fact that you know the sex of the first child means nothing. There is no excluding anything because of it.

It's very simple.

 

[viking611]

In the US, 0.033% to 0.05% of babies are born as hermaphrodites so that messes everyone's answer up!

 

[Illini]

Come on you 50%ers talking like you know for sure.

I will bet any amount of money that the answer is 2/3.

This is a betting forum, bring it on.

All you can eat, bro.

 

[Geoff101]

Suppose you have three cards:

• a black card that is black on both sides,
• a white card that is white on both sides, and
• a mixed card that is black on one side and white on the other.

You put all of the cards in a hat, pull one out at random, and place it on a table. The side facing up is black. What are the odds that the other side is also black?
The answer is that the other side is black with probability 2/3. However, common intuition suggests a probability of 1/2 because across all the cards, there are 3 white, 3 black. However, many people forget to eliminate the possibility of the "white card" in this situation (i.e. the card they flipped CANNOT be the "white card" because a black side was turned over).
In a survey of 53 Psychology freshmen taking an introductory probability course, 35 incorrectly responded 1/2; only 3 students correctly responded 2/3.

different situation altogether....we're talking the outcome of one event based on 2 possible outcomes...what is the sex of a random person....given that they have a brother.

ok lemme ask this, of all the people in the world that have brothers' what percentage are female and male.....?

 

[festeringZit]

http://en.wikipedia.org/wiki/Boy_or_Girl_paradox

Um, I already posted this link on here twice.

 

[Illini]

I am shocked at how smart, successful people cannot follow basic logic.

 

[festeringZit]

I am shocked at how smart, successful people cannot follow basic logic.

I guess I should throw out my graduate degrees, and tell my probability
prof that I had to throw out his degree too huh?

hno:

How much do you want to bet?

 

[Illini]

I guess I should throw out my graduate degrees, and tell my probability
prof that I had to throw out his degree too huh?

hno:

How much do you want to bet?

Any amount.

 

[Geoff101]

put me down for a c-note and a trip down to Austin to employ the odds in a field test

 

[Illini]

Before you start having kids the probabililty of having two boys is 25%. The probability of having two girls is 25%. The probability of having one of each is 50%.

Once you have the first child, the odds change, because you can eliminate the two girls scenario. Now, the probability of having two girls is zero. The probability of having a boy and girl is 50%. The probability of having two boys is 50%.

If you believe otherwise, you are wrong.

 

[festeringZit]

put me down for a c-note and a trip down to Austin to employ the odds in a field test

There is no need for a field test, you can write a simple computer
program to simulate it.

 

[festeringZit]

Before you start having kids the probabililty of having two boys is 25%. The probability of having two girls is 25%. The probability of having one of each is 50%.

Once you have the first child, the odds change, because you can eliminate the two girls scenario. Now, the probability of having two girls is zero. The probability of having a boy and girl is 50%. The probability of having two boys is 50%.

If you believe otherwise, you are wrong.

We are not talking about looking at odds once you have the first child, we
are talking about looking at families that have already had two kids.

There is a huge difference.

 

[CoolBreeze22]

I think we can all agree that laying 3/2 in a survey that someone's second child is a girl would leave Zit homeless.