The construction time for a bridge depends on the weather Th

The construction time for a bridge depends on the weather. The project is expected to take 250 days if the weather is dry and hot. If the weather is damp and cool, the project is expected to take 350 days. Otherwise, it is expected to take 300 days. Historical data suggest that the probability of cool, damp weather is 30% and that of dry, hot weather is 20%. Compute the project’s expected completion time.

Solution

for the expected value of completion time we need the probabilities

we have that damp and coll is 0.30

dry hot is 0.20

for other 1 - 0.30 - 0.20 = 0.50

so expexted completion time is expected to take for each weather multiply by the probability of each weather

250 * 0.20 + 350 * 0.30 + 300 * 0.50

305

project’s expected completion time. = 305