Answer: b. $5.4
Step-by-step explanation:
First calculate the Expected return;
Expected cashflow = ∑ (Probability of cashflow * cashflow)
Expected cashflow = (5 * 0.2) + (12*0.3) + (18*0.3) +(20*0.2)
=$14
Standard deviation = √∑ [Probability * (CF - Expected CF)^2]
Standard deviation= √[(0.2*(5 - 14)^2) + (0.3*(12-14)^2) + (0.3*(18-14)^2) + (0.2*(20-14)^2)
Standard deviation = $5.4