Differential Analysis and Decision Making

Why do we say differential analysis is the key to decision making? Explain the difference between relevant and irrelevant costs by using examples. Cover the topics: adding or dropping product lines, make or buy decisions, and sell or process further decisions.

NOTE: Hello Scholars, There is a hierarchy of authority as it relates to academic research i.e. Refereed journals, professional publications, websites that have the following suffices in order of authority: .gov; .edu; .org and selected .com websites. Please do not use the following websites below (and others like them) as reference sources for your papers or your discussion posts. They lack academic rigor for a Graduate level program such as University’s. While these sources help clarify concepts, they should not be your primary source for academic research. University’s elibrary is an easily accessible source for scholarly reference sources.
As always, wikipedia and investopedia are also not acceptable sources for academic research.

Thank you,
please do not used any of these website also
Accountingexplanation.com
Accountingtools.com.
http://www.accountingtools.com/questions-and-answers/
Accountingexplained.com
smallbusiness.chron.com
accountingcoach.com