6. Difference between Quality Assurance, Quality Control and Testing?

Many people and organizations are confused about the difference between quality assurance (QA), quality control (QC), and testing. They are closely related, but they are different concepts. Since all three are necessary to effectively manage the risks of developing and maintaining software, it is important for software managers to understand the differences. They are defined below:

Quality Assurance: A set of activities designed to ensure that the development and/or maintenance process is adequate to ensure a system will meet its objectives.

Quality Control: A set of activities designed to evaluate a developed work product.

Testing: The process of executing a system with the intent of finding defects. (Note that the "process of executing a system" includes test planning prior to the execution of the test cases.)

The quality assurance is a process for providing adequate assurance that the software products and processes in the product life cycle conform to their specific requirements and adhere to their established plans.

The purpose of Software Quality Assurance is to provide management with appropriate visibility into the process being used by the software project and of the products being built; while testing in itself cannot ensure the quality of software. 

All testing can do is give you a certain level of assurance (confidence) in the software. On its own, the only thing that testing proves is that under specific controlled conditions, the software functioned as expected by the test cases executed.