P(X≠Y) question about probability and union

[gate13]

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[X∪Y ] which means :

Pr[X⋃Y ]=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 April 26, 2015 by gate13

[timo]

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.

[Sensei]

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 April 26, 2015 by Sensei

[gate13]

Sensei,

you are off the topic!sorry!

timo!!!!

all the letters are X and Y...

They are all capital!

 

Never mind guys!

[Sensei]

This is computer science forum,

so you're off-topic.

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

[gate13]

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

did you know math and computer sicence were related?

lol

Edited April 26, 2015 by gate13

[imatfaal]

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