Answer
$(2,1)$.
Work Step by Step
The midpoint $M$ of the line segment from $P_1(x_1,y_1)$ to $P_2(x_2,y_2)$ is:
$M=\left(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2}\right)$
Thus, the midpoint of the line segment joining the two given points is:
$M=\left(\frac{-1+5}{2},\frac{3+-1}{2}\right)=(2,1)$