i have tried and reviewed every formula over and over but still get an answer that is said to be wrong.

need help in calcuating the variance and standard deviation. i have tried and reviewed every formula over and over but still get an answer that is said to be wrong. help.

state of economy - probability- stock a- stock b- stock c

boom: 0.15;0.32;0.42;0.33

normal: 0.45; 0.19; 0.13; 0.12

poor: 0.30; -0.05; -0.08;-0.06

bust: 0.10;-0.16;-0.28;5 -0.09

portfolio percent is 30 % for A & C; and 40 % for b.

need to see the calculations for

expected return; variance; and standard deviation. i can't figure out where my errors are.