SOLUTION: Find the mean and standard deviation of the following probability distribution: x 1 2 3 P(x) 0.1 0.8 0.1

Algebra ->  Probability-and-statistics -> SOLUTION: Find the mean and standard deviation of the following probability distribution: x 1 2 3 P(x) 0.1 0.8 0.1       Log On


   

Question 668663: Find the mean and standard deviation of the following probability distribution:
x
1
2
3

P(x)
0.1
0.8
0.1
Answer by swincher4391(1107) About Me  (Show Source):
You can put this solution on YOUR website!
mean = E[X] = x*P(x) for each x = 1*.1 + 2*.8 + 3* .1 = .1 + 1.6 + .3 = highlight%282%29
Calculate E[X^2] in order to find Variance. E[X^2] = 1^2 * .1 + 2^2 *.8 + 3^2 * .1 = .1 + 3.2 + .9 = 4.2
Var[X] = E[X^2] - E[X]^2 = 4.2 - 2^2 = 4.2 - 4 = .2
SD[X] = sqrt(Var[X]) = sqrt(.2) = highlight%28.4472%29