Question 1149778
E(x) is sum of all x*p(x)
=0+0.25+0.40+0.45+0.40+0.50
=2
V(x)=sum of sqrt (differences)^2*x
=4(0.20)=0.80
+0.25+0+0.15+0.40+0.90=2.50
sd is sqrt (V)=sqrt(2.5)=1.58