1. Craps Dice Roll Probability Rules
2. Craps Dice Roll Probability
3. Craps Dice Roll Probability Rule

Dice Roll Probability. The chance of rolling a total of 2 is 2.78 percent The chance of rolling a total of 3 is 5.56 percent The chance of rolling a total of 4 is 8.33 percent The chance of rolling a total of 5 is 11.11 percent The chance of rolling a total of 6 is 13.89 percent The chance of rolling a total of 7 is 16.67 percent The chance of. In a game of craps, you roll two fair dice. Whether you win or lose depends on the sum of the numbers occurring on the tops of the dice. Let x be the random variable that represents the sum of the numbers on the tops of the dice. What is the probability distribution of these x values (that is, what is the probability that x = 2, 3, etc.)? Understanding dice rolling probabilityisn't much different than a coin flip probability. A coin has two sides. If you flip a coin,probability dictates that either heads or tails have a 50% chance of coming up. If you choose heads before the flipping of a coin, then there's 1 way of 2 that would happen. In craps: Rolling a sum of 2, 3 or 12 on the first roll of the dice is a loss. What is the probability of losing on the first roll? Rolling a sum of 4, 5, 6, 8, 9, or 10, on the first roll is.

Hey Wizard,
I'm a CJ/CIS major working in a Math department, and I've been asked to convert an open ended question test to multiple choice test. I found your site 'The Wizard of Odds', and was directed here to ask my question. What is the probability of rolling a 2 given your roll only being even, when rolling a 20 sided die? Thank you for your help.
-R

I know what you probably meant, but you actually need to specify what's on the 20-sided die. If it's 10 through 200 in increments of 10, the probability is zero.
Under the assumption that the d20 contains integers 1..20, here are the answers I'd list on a four-choice pick:
a) 1/2
b) 1/5
c) 1/10

Craps Dice Roll Probability Rules

d) 1/20
Edit: What's a 'CJ' major?

I know what you probably meant, but you actually need to specify what's on the 20-sided die. If it's 10 through 200 in increments of 10, the probability is zero.
Under the assumption that the d20 contains integers 1..20, here are the answers I'd list on a four-choice pick:
a) 1/2
b) 1/5
c) 1/10
d) 1/20
Edit: What's a 'CJ' major?

Funny, I read it differently for the same reason. I 'decided' the question stipulated the 20 sides were numbered 2 thru 20, evens only, with 2 identical sides per number, before I read ME's answer. Be interested to see the clarification.
I'm guessing 'Criminal Justice/Crime Scene Investigation' for the major.

If you're saying 'I've got a d20. The next roll will be an even number. What are the odds of that number being a 2?' Then I'd have to say the odds are 1 in 10. But how does one guarantee that no odd number will be rolled?

It's a conditional probability problem. It's guaranteed because the question says it's guaranteed. It's a math question, not a physics question.Designing multiple-choice tests is one of my favorite things to do. I see this question, and all I think is 'gosh, i wonder how they're doing answer placement. Is it randomized? Rotated? both?'

Craps Dice Roll Probability

My HS world geography teacher was a sadistic guy. He put patterns into all his tests, but he also rotated the correct answers. So my 100% score could go a,b,c,d,a,b,c,d... while my friend could have the same answers but need to respond d,c,b,a,d,c,b,a... Made colluding and/or selling answers a real pain.

CJ - Criminal Justice
The numbers on the 20 sided dice are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20. If this reply sounds smartalically, I appologize. I don't really understand what you mean needing to 'specify what's on the 20-sided die.' Anyhow, which is the answer; a, b, c, or d?

There are 10 even numbers. If you know for sure that it is even, then the answer is 1/10.
You can also solve this by going through the formula for conditional probability. To be honest I always have to look it up (check wikipedia for conditional probability), but you will end up dividing 1/20 by 10/20 and get 1/10.

Craps Dice Roll Probability Rule