The line graph reveals the usage of time it would take for three companies to manufacture a refrigerator over a period time of 10 years.
Overall, it exhibites two different patterns among 3 companies. Company A and company C had a similar progress tendency, while company B experienced a total different one.
To be specific, though company C experienced a constanly decrease, commencing at 35 hours and descended to under 30 hours at the end of the period, which always had the longest time to manufacture a refrigerator. Same progress trajectory can be observed in company A, which needed 30 hours in 1990 and finally dropped to around 20 hours in 2000, making it become the most efficency manufacturer. In contrast, company B after ten years of stable progress, still had more than 25 hours to manufacture a fridge.
