Let's say that we have 2 fair dice and we throw them at the same time. If I want to describe the probability filed will the event (1,2) be the same with (2,1)? By event (x,y) I mean that the first dice shows x and the second y.
1 Answer
$\begingroup$
$\endgroup$
5
If we coloured the dice one red and the other blue then the probability that the red has 1 and the blue has 2 is $\frac{1}{36}$.
Similarly if we wanted the blue to have 1 and the red 2 the probability is $\frac{1}{36}$.
As these events are mutually exclusive the probability of getting 1 or 2 regardless of which die they are on is $\frac{2}{36}$
-
$\begingroup$ If they had the same color, then what it the probability of getting 1 or 2? $\endgroup$– SebiSebiApr 29, 2015 at 19:51
-
-
$\begingroup$ Ok. But then what is the difference with picking a ball from a bag. If we have 2 red balls and 4 blue, then one will calculate the probability of picking a red balls using combinations and not arrangements. $\endgroup$– SebiSebiApr 29, 2015 at 20:13
-
$\begingroup$ How many balls are you selecting? Are you replacing the balls? $\endgroup$– KarlApr 29, 2015 at 20:15
-
$\begingroup$ Sorry, my mistake. There are 5 red balls and 4 blue, and I want to select 3 red balls. $\endgroup$– SebiSebiApr 29, 2015 at 20:55