1-In addition to high correlation between two variable, what's the other factor to consider the cause and effect?

2-What are the common types of relevant costs and irrelevant costs?

3-Generally, what is the time horizon for capital budget?

4-What factors other than quantitative are important to consider in making capital budget decisions?

5- Should a company accept all for investment proposals with positive NPV investment? Why or why not? What situation may a company should accept for investment all positive NPV investment alternatives?