## Elementary Statistics (12th Edition)

It is a probability distribution because $\sum P(x)=0.0625+0.25+0.375+0.25+0.0625=1$. Mean $0\cdot0.0625+1\cdot0.25+2\cdot0.375+3\cdot0.25+4\cdot0.0625=2$. Standard deviation: $\sqrt{(0-2)^2\cdot0.0625+(1-2)^2 \cdot0.25+(2-2)^2\cdot0.375+(3-2)^2\cdot0.25+(4-2)^2\cdot0.0625}=1$.