What are the definitions of Quality Control and Quality Assurance?

In tech class we need to find out what Quality Control and Quality Assurance are, in terms of creating and building quality products. Can anyone help?What are the definitions of Quality Control and Quality Assurance?
Quality assurance is developing systems that assures quality. For example, a QA engineer may develop quality plans for manufacturing including statistical process control systems. Generally these are developed after extensive consultations with the customer or people who keep in touch with customer. He/she may also provide quality specifications to other organizations.





Quality control deals with actually monitoring products. For example, people who check incoming quality are involved with QC work.What are the definitions of Quality Control and Quality Assurance?
Quality Assurance is a process for checking the product 'designed' and/or 'developed' and/or 'produced'.





Let us take simple example of Foot ball. It is designed by a design engineer to be produced with some rubber with thickness t. QA will check whether this thickness football will be good for at least double the play time. Along with the weather conditions and forces that can effect with the kicks it is getting on.





Once product manufacturing data is made as per QA checks, then this data is made as standard and Quality Control person will keep on checking in process of the product manufacturing whether this product is been produced as per plan. It can at each stage check or before delivering to the end customer check etc.
Rajashekhar Shivaram gave you a very good description of how it would be in a large enterprise





most businesses need to make a profit to survive


if you check everything that is being done and you need to check those who check's...your business will die!


the plan has to be economical.





another way to present it is


consider the chief of police, he or she has to insure the quality of life of the citizens


how many police agents do you put and where to distribute speeding tickets?





if they are always monitoring the same place, people will not speed at that location anymore, the defect will go away!


They will go race somewhere else.





so they (the quality control people) have to be relocated on a periodic and random basis. This is the QA plan


the police officers do the quality control








Guru