In: Statistics and Probability
Given the following discrete uniform probability distribution,
find the expected value and standard deviation of the random
variable. Round your final answer to three decimal places, if
necessary.
x | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
---|---|---|---|---|---|---|---|---|---|---|---|
P(X=x) | 1/11 | 1/11 | 1/11 | 1/11 | 1/11 | 1/11 | 1/11 | 1/11 | 1/11 | 1/11 | 1/11 |
Solution:
x | P(x) | x * P(x) | x2 * P(x) |
0 | 0.09 | 0.301 | 0 |
1 | 0.09 | 0.09 | 0.09 |
2 | 0.09 | 0.18 | 0.36 |
3 | 0.09 | 0.27 | 0.81 |
4 | 0.09 | 0.36 | 1.44 |
5 | 0.09 | 0.45 | 2.25 |
6 | 0.09 | 0.54 | 3.24 |
7 | 0.09 | 0.63 | 4.41 |
8 | 0.09 | 0.72 | 5.76 |
9 | 0.09 | 0.81 | 7.29 |
10 | 0.09 | 0.9 | 9 |
1 | 5.251 | 34.65 |
Mean = = x P (x ) = 5.251
Standard deviation = = x2 P (x ) - ( )2
= 34.65- ( 5.251 )2
= 34.65 - 27.57
= 7.08
= 2.661