please answer this question and explain in depth as i dont understand $($Statistics$)$Problem $1($CLO#$2)$

A modem transmits a $+2$ voltage signal into a channel.

The channel adds to this signal a noise term that is drawn from the set $\{0,-1,-2,-3\}$ with

respective probabilities $\{\frac{4}{10},\frac{3}{10},\frac{2}{10},\frac{1}{10}\}.$

Find the expected value of the modem signal and construct a probability distribution histogram, marking

the identified expected value on it$..$