x -5 -1 2 7 10
P(x)0.15 0.08 0.22 0.18 0.37
Determine the expected value of x.
Determine the standard deviation of x.
Stick to the definitions,
$\displaystyle E(X)=\Sigma_{i=1}^{n}x_iP(x_i)}$
and
$\displaystyle SD(X)=\sqrt{\Sigma_{i=1}^{n}\left[x_i-E(X)\right]^2P(x_i)}}$ or
$\displaystyle SD(X)=\sqrt{E(X^2)-E(X)^2}$
Next time please show where you cannot understand, because for me this seems quite basics