Question

in a game involving a pair of fair dice a player rolls the dice until he gets a sum of 7 let z equal the number of rolls it takes a player to get the sum

Answer 1

There is no fixed number of trials, so Z is not binomial variable.

Explanation:

Khan

Answer 2

z = 36 rolls , probability for getting 7 = 1/6

Explanation:

A die has 6 possible outcomes, which sums to 36 for two dice for every value on both dice.

The outcomes for rolling both dice for 36 times gives 6 possible outcomes summing to 7, that is, (1, 6), (2, 5), (3, 4), (4, 3), (5, 2), and (6, 1).

There the probability of getting a sum dice of 7 is:

= 6 / 36 = 1/6