E(Y)=(\(\frac{1}{n}\))Σ(k=1\(\vec{n}\))(3k+2)
=(\(\frac{1}{n}\)){3・(\(\frac{1}{2}\))n(n+1)+2n}
=(\(\frac{1}{2}\))(3n+7)

V(Y)=E(\(Y^{2}\))-{E(Y)}^2
=(\(\frac{1}{n}\))Σ(k=1\(\vec{n}\))(3k+2\()^{2}\)
-{(\(\frac{1}{n}\))Σ(k=1\(\vec{n}\))(3k+2)}^2
=(\(\frac{1}{n}\))Σ(k=1\(\vec{n}\))(9\(k^{2}\)+12k+4)-{(\(\frac{1}{2}\))(3n+7)}^2
=……
=(\(\frac{1}{2}\))(6\(n^{2}\)+21n+23)-(\(\frac{1}{4}\))(9\(n^{2}\)+42n+49)
=(\(\frac{3}{4}\))(\(n^{2}\)-1)
=(\(\frac{3}{4}\))(n+1)(n-1)

EX=(1+2+...+n)/n=(n+1)/2

V(X)=E(X-(n+1)/2\()^{2}\)=E(\(x^{2}\))-{(n+1)/2}^2
=(n+1)(2n+1)/6-(n+1\()^{2}\)/4=(n+1)(n-1)/12

EY=E(3X+2)=3EX+2=3(n+1)/2+2=(3n+7)/4

V(Y)=V(3X+2)=\(3^{2}\)*V(X)=9(3n+7)/4