 # simulation of unfair dice

how can i simulate the unfair dice with the use of prob function ?

sample_function <- sample (die =1:4, size=20,replace = TRUE, prob = c(1/2,1/6,1/6,1/6)))
sample_function

Hi @tanjina,

You are on the right track! You just made a few mistakes in your code and I'll help you correct them. But before I do, I'd like to point out that `prob` is not a function, but it is an argument of the `sample()` function. Having said that, here are the mistakes you made:

• the first argument of the `sample()` function is always `x`, so you should have written: `x = 1:4` and not `die = 1:4`.

• you added an extra closing parenthesis `)` that is not needed here.

So the correct code should be:

``````unfair_die_roll <- sample (x  = 1:4, size = 20, replace = TRUE, prob = c(1/2, 1/6, 1/6, 1/6))
unfair_die_roll
``````

Note that I changed the name of the variable that you created from `sample_function` to `unfair_die_roll` even though it does not affect the result.

2 Likes

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.

The simulation that your code performs IS unfair. You have:

• `x = 1:4` and
• `prob = c(1/2, 1/6, 1/6, 1/6)`

The reason why it is unfair is because all outcomes do not have the same probability:

• the outcome `1` has a 50% (or `1/2`) chance of landing each time you roll
• the outcomes `2`, `3` and `4` all have a 16.66% (or `1/6`) percent chance of landing at each roll

Because all outcomes do not have the same probability, we say that the die is unfair. But actually, you have to remember that a die has 6 sides and not 4. So, the true way of rolling an unfair die would be something like:

``````sample(x = 1:6, size = 20, replace = TRUE, prob = c(0.2, 0.1, 0.1, 0.3, 0.05, 0.25))
``````

So now, we have 6 sides and all sides have different probabilities of landing.

What you need to remember is that all the probabilities' sum must equal to `1`.

1 Like

Thank you so much . i wanted to know that how can i simulate the below result for unfair dice . is it still remain same .

sample_function <- sample (x =1:4, size=20,replace = TRUE, prob = c(1/2,1/6,1/6,1/6))

You are very welcome.

okay . now i understand. Thank you so much