The Table Below Is the Probability Table for a Random

Short Answer

The table below is the probability table for a random variable X. Find Var(X). $$\begin{array} { l | l l l l } \text { Outcome } & - 1 & 0 & 1 & 2 \\\hline \text { Probability } & \frac { 3 } { 7 } & \frac { 1 } { 7 } & \frac { 1 } { 7 } & \frac { 2 } { 7 }\end{array}$$ Enter just a reduced fraction of form $\frac { a } { b }$ .