In: Statistics and Probability
Two 6-sided dice are rolled. One die is a standard die, and the other is a Fibonacci die with sides 1, 1, 2, 3, 5, and 8.
a. What is the probability distribution of this experiment?
b. What is the shape of the probability distribution?
c. What is the expected value when these 2 dice are rolled?
a)
The outcome (sum) of the roll of two die,
Fabonacci die | |||||||
1 | 1 | 2 | 3 | 5 | 8 | ||
Standard die | 1 | 2 | 2 | 3 | 4 | 6 | 9 |
2 | 3 | 3 | 4 | 5 | 7 | 10 | |
3 | 4 | 4 | 5 | 6 | 8 | 11 | |
4 | 5 | 5 | 6 | 7 | 9 | 12 | |
5 | 6 | 6 | 7 | 8 | 10 | 13 | |
6 | 7 | 7 | 8 | 9 | 11 | 14 |
The probability distribution of this experiment is,
Sum | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
Prob | 2/36 | 3/36 | 4/36 | 4/36 | 5/36 | 5/36 | 3/36 | 3/36 | 2/36 | 2/36 | 1/36 | 1/36 | 1/36 |
b)
The frequency distribution of this experiment is,
Sum | Frequency |
2 | 2 |
3 | 3 |
4 | 4 |
5 | 4 |
6 | 5 |
7 | 5 |
8 | 3 |
9 | 3 |
10 | 2 |
11 | 2 |
12 | 1 |
13 | 1 |
14 | 1 |
The column plot (histogram) for this frequency is shown below,
The frequency distribution is normally distributed with slightly right tailed distribution.
c)
The expected value is obtained using the formula,
Sum, X | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
Prob, P(X) | 2/36 | 3/36 | 4/36 | 4/36 | 5/36 | 5/36 | 3/36 | 3/36 | 2/36 | 2/36 | 1/36 | 1/36 | 1/36 |
Sum, X | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 |
Prob, P(X) | 0.06 | 0.08 | 0.11 | 0.11 | 0.14 | 0.14 | 0.08 | 0.08 | 0.06 | 0.06 | 0.03 | 0.03 | 0.03 |
X*P(X) | 0.111 | 0.25 | 0.444 | 0.556 | 0.833 | 0.972 | 0.667 | 0.75 | 0.556 | 0.611 | 0.333 | 0.361 | 0.389 |