In: Statistics and Probability
A regular six-sided die and a regular eight-sided die are rolled to find the sum. Determine the probability distribution for the sum of the two dice. Create a frequency histogram for the probability distribution and determine the expected sum of the two dice.
Solution:-
The probability distribution for the sum of the two dice.
Sum(x) | Frequency | P(x) |
2 | 1 | 0.020833 |
3 | 2 | 0.041667 |
4 | 3 | 0.0625 |
5 | 4 | 0.083333 |
6 | 5 | 0.104167 |
7 | 6 | 0.125 |
8 | 6 | 0.125 |
9 | 6 | 0.125 |
10 | 5 | 0.104167 |
11 | 4 | 0.083333 |
12 | 3 | 0.0625 |
13 | 2 | 0.041667 |
14 | 1 | 0.020833 |
Sum | 48 | 1 |
The frequency histogram for the probability distribution is
The expected sum of two dices is 8
Sum(x) | Frequency | P(x) | x*P(x) |
2 | 1 | 0.020833 | 0.041667 |
3 | 2 | 0.041667 | 0.125 |
4 | 3 | 0.0625 | 0.25 |
5 | 4 | 0.083333 | 0.416667 |
6 | 5 | 0.104167 | 0.625 |
7 | 6 | 0.125 | 0.875 |
8 | 6 | 0.125 | 1 |
9 | 6 | 0.125 | 1.125 |
10 | 5 | 0.104167 | 1.041667 |
11 | 4 | 0.083333 | 0.916667 |
12 | 3 | 0.0625 | 0.75 |
13 | 2 | 0.041667 | 0.541667 |
14 | 1 | 0.020833 | 0.291667 |
Sum | 48 | 1 | 8 |
E(x) = x*P(x)
E(x) = 8