An example of a randomized controlled experiment is when a. Some 5th graders in a specific elementary school are allowed to use computers at school while others are not and their end-of-year performance is compared holding constant other factors
b. random variables are controlled for by holding constant other factors
c. one US state increases minimum wages and an adjacent state does not, and employment differences are observed
d. households receive a tax rebate in one year but not the other

*to gain a comparative advantage

*to increase efficiency

Explanation:

Specialization is when a firm or a country concentrates on producing a few items. The firm chooses and focuses on producing the goods that it has a comparative advantage. Specialization means that a firm will manufacture the goods that it uses fewer inputs in production compared to other producers.

Specialization increases the efficiency of a company. As the company focuses on producing a few items,  workers become experts, which means they will spend fewer hours in accomplishing their tasks. The process flow in the production becomes more seamless as a greater understanding between sections is enhanced through the specialization.  Mistakes that lead to losses are reduced. Due to increased efficiency, the firm products will be cheaper compared to competitors, which results in the firm gaining comparative advantage.