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gate13

P(X≠Y) question about probability and union

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hi i have a table and one of the questions is

P(X≠Y)

I am so confused!

does this mean is the same as Pr[XY ] which means :

Pr[XY ]=Pr[X]+Pr[Y]-Pr[X Y]

Please help

!


for example the table is something like that:

 

y

x 1 2 3 4

1 0.02 0.02 0.02 0.04

2 0.04 0.04 0.04 0.08

3 0.14 0.14 0.14 0.28

Edited by gate13

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Depending on the context there may be different interpretations. The simplest one would be the following. You take a random variable x and a random variable y. The probabilities for each combination are given in your table. Question: What is the probability that x and y do not have the same value?

 

Sidenote: Strictly speaking is it impossible to answer questions about mathematical expressions when the meaning of the letters that appear is not given. Effectively, their meaning can often be assumed - e.g. in the context of a physics problem with only one body one often assumes that "m" means the mass of the body. But for X and Y (capital letters) combined with a table that lists x and y (non-capital letters) assuming things about the meaning from only the letters is highly speculative.

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2 dimensional table should be table[][] not table[].

2d table can be squashed to 1d table by f.e. table[y*columns+x]

 

Are you mathematician who want to write computer program?

 

Equality operator in computer programs is ==

Not-equal operator is !=

Edited by Sensei

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Sensei,

you are off the topic!sorry!


timo!!!!

all the letters are X and Y...

They are all capital!

 

Never mind guys!

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This is computer science forum,

so you're off-topic.

I see no computer programming related questions in your post..

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Yes, this is a topic in one of my computer science classes.....

did you know math and computer sicence were related?

lol

Edited by gate13

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you have a table of outcomes - 12 in all - that give the probability for any of three x outcomes and four y outcomes; check that the total comes to 1. Those in which x give same outcome as y ie x=1 y=1 should be excluded - the remainder is the probability that x =/= y

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