Variance, standard deviation and linear variance of a discrete random variable
Let X be the difference between two recorded counts
The distribution of \(X\) is given below
| \(x\) | \(\Pr(X=x)\) |
|---|---|
| \(9\) | \(\frac{1}{8}\) |
| \(10\) | \(\frac{3}{4}\) |
| \(11\) | \(\frac{1}{8}\) |
Use the table of squared-value products below. The symbol ? marks an entry to complete
| \(x\) | \(\Pr(X=x)\) | \(x^2\Pr(X=x)\) |
|---|---|---|
| \(9\) | \(\frac{1}{8}\) | ? |
| \(10\) | \(\frac{3}{4}\) | ? |
| \(11\) | \(\frac{1}{8}\) | \(\frac{121}{8}\) |
What is the value of Var(X)? Give the exact value