How do theoretical concepts affect business management?

It allows you to analyze data and make conclusions. So lets say you want to open a t- shirt store and you have 3 different color shirts. and 6 in all. You have the 3 blue shirts, 2 red shirts, and 1 yellow shirt. You can assume that if you price the yellow shirt a higher price than the blue most people will buy the cheaper shirt. so you can use the theoretical concepts to assume prices of things, what to charge and other financial business including profits.