Dice question

  • Thread starter deep519
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  • #1
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Hi guys,

I have a very simple but confusing problem that I have with die.

It's not a homework problem, more a general understanding question.

Now, question (im my own words)

Four six-sided die are rolled together and independently to each other.
Is the chance to roll a sum of (even) or (odd) the same or is rolling even higher.


Now, i think that rolling four die, the chances that their sum are even is higher than rolling odd for the reason that the possible combination's - reminded that it doesn't matter which order the dice are rolled are:

Where 1 means odd and 0 is even
0 0 0 0 = Even
0 0 0 1 = Odd
0 0 1 1 = Even
0 1 1 1 = Odd
1 1 1 1 = Even

Unless I am missing something, there is a higher chance to roll even since 3E > 2O.

Maybe this is a very fundamental stats problem, but i'm a little confused.

Me and friend are arguing about it, so if somebody could clarify the correct answer.
 
Last edited:

Answers and Replies

  • #2
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you missed something, look at all the possible outcomes

0 0 0 0 : even
0 0 0 1 : odd
0 0 1 0 : odd
0 0 1 1 : even
0 1 0 0 : odd
0 1 0 1 : even
0 1 1 0 : even
0 1 1 1 : odd
1 0 0 0 : odd
1 0 0 1 : even
1 0 1 0 : even
1 0 1 1 : odd
1 1 0 0 : even
1 1 0 1 : odd
1 1 1 0 : odd
1 1 1 1 : even

So 8 times even so chance you have even is 50% so equal chances.
 
  • #3
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Well, the thing is order should not matter since if four dice are rolled, you will get only those 5 combinations.

0110 or 1100 would still mean two dice were even and two were odd, thus why would the order matter.

1110 or 1011 same thing... ect..

We are just concerned with the chance that the sum is even or odd.
 
  • #4
chiro
Science Advisor
4,790
132
Well, the thing is order should not matter since if four dice are rolled, you will get only those 5 combinations.

0110 or 1100 would still mean two dice were even and two were odd, thus why would the order matter.

1110 or 1011 same thing... ect..

We are just concerned with the chance that the sum is even or odd.
It is true that you are interested in the frequency and not the order but you have to take into account the frequency which is what the above poster has pointed out.

When interested in unordered sets we use nCr so for the frequency we get

0 0 0 0 - x 1
0 0 0 1 - x 4
0 0 1 1 - x 6
0 1 1 1 - x 4
1 1 1 1 - x 1

Total frequency - 16
Total even - 1 + 6 + 1 = 8 = 50%
Total odd - 4 + 4 = 8 = 50%
 

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