Chapter 3 - Section 3-4 - Mean and Variance of a Discrete Random Variable - Exercises - Page 77: 3-68

$μ=\approx565$ $σ²=6875$ $σ\approx82.92$

$μ=E(x)=∑xP(x)=350×0.06+450×0.1+550×0.47+650×0.37\approx565$ $E(x²)=∑x²P(x)=350²×0.06+450²×0.1+550²×0.47+650²×0.37=326100$ $σ²=V(x)=E(x²)-[E(x)]²=6875$ $σ=\sqrt σ²\approx82.92$