In order to calculate the sum we need to iterate over the "xi" variable going from 1 to 14 and adding all the data.
[tex]\begin{gathered} \sum ^{\infty}_{n\mathop=1}\frac{x_i}{50}\text{ = }\frac{38\text{ - 82}+19+84-37.93-31-73-50-65-31-85-48}{50} \\ \sum ^{\infty}_{n\mathop{=}1}\frac{x_i}{50}\text{ = }\frac{-361.93}{50}\text{ = -7}.2386 \end{gathered}[/tex]The answer is approximately -7.24.