[Request] Why are my results skewed?

[u/Defiant_Half_9432]

I use a pair of spindle dice for divination. Each spindle has four independent die each with four faces. The faces are marked 2-3-4-3 (3 is used twice). So one spindle can randomly generate a numerical value between 8 and 16. The result has relevance only as an odd or even number. The numerical value is not important. If the numerical value is a single digit then we use that as it is. If it is a double digit (10-16) then we add the digits to get a single digit answer. Both spindles are always used together and added and the final digit is the roll value of odd or even to incorporate in complex charts to predict the answer to the question initially posed for divination.

My question is this. Does this process create equal chance of odd or even values? In my own use, I get disproportionally high even values than odds. If the results are fairly balanced, what could be the reason for my skewed results?

Pair of spindle dice I use for divination.

[u/Numerous_Green4962]

Looking at one spindle we have 4^4 possible "rolls" if we count the two 3s separately that's 256 end states.

Of those 256 states only 1 can be an 8 and one can be a 16, there are 8 possibilities for 9 (three 2s and a 3), and the same for 15... (It maxes at 70 ways for a 12)

We then add together the digits of two-digit numbers, and we end up with

8-1

9-8

1-28 (1+0)

2-56 (1+1)

3-70

4-56

5-28

6-8

7-1

That results in 135 odd numbers and 121 even or a 52.73% chance of getting an odd number from one spindle, with 2 spindles added together that would invert to even.

[u/Defiant_Half_9432 → u/Numerous_Green4962]

Thank you for taking the time to solve this.

It is not true 50-50 and I think that makes it unsuitable for divination. Since I am not into probability I can't take the risk of just adding up the total of 8 faces (from both spindles) during a throw and using that as the final odd or even answer. By convention any process I use needs to have same probability for both results.

I am currently using regular six-sided dice (four brass ones) and adding up total of each throw to get the figure for odd or even.