The following table shows part of the probability distribution for a random variable x.
x f(x)
0 0.2
1 ?
2 0.15
3 ?
4 0.15
a. The mean of the above distribution is known to be 1.8 (i.e., E(x) = 1.8). Determine f(1) and f(3).
b. Compute the variance and the standard deviation for the above probability distribution.