Answer
(a) $∑X^2=50$
(b) $(∑X)^2=144$
(c) $∑(X-3)=0$
(d) $∑(X-3)^2=14$
Work Step by Step
(a) $∑X^2=1^2+6^2+2^2+3^2=1+36+4+9=50$
(b) $(∑X)^2=(1+6+2+3)^2=12^2=144$
(c) $∑(X-3)=(1-3)+(6-3)+(2-3)+(3-3)=-2+3-1+0=0$
(d) $∑(X-3)^2=(1-3)^2+(6-3)^2+(2-3)^2+(3-3)^2=(-2)^2+3^2+(-1)^2+0^2=4+9+1+0=14$
