20.14 Estimating sales. Gain Communications sells aircraft communications units. Next year’s sales depend on market conditions that cannot be predicted exactly. Gain follows the modern practice of using probability estimates of sales. The sales manager estimates next year’s sales as follows:
| Units sold: | 6000 | 7000 | 8000 |
| Probability: | 0.1 | 0.2 | 0.4 |
| Units sold: | 9000 | 10,000 | |
| Probability: | 0.2 | 0.1 |
These are personal probabilities that express the informed opinion of the sales manager. What is the sales manager’s expected value of next year’s sales?