Seventh, because the immune system is weak it cannot kill enough cancer cells and the cancer cells grow out of control. Thus, in summary, the root cause of cancer is microbes and parasites that are in the organs or colon (or bloodstream), which weakens the immune system. However, other things can cause cancer.
Test Reliability and Validity Defined Reliability. Test reliablility refers to the degree to which a test is consistent and stable in measuring what it is intended to measure. Most simply put, a test is reliable if it is consistent within itself and across time.
Validity & Reliability Of Methods. Assessment methods and tests should have validity and reliability data and research to back up their claims that the test is a sound measure. Reliability is a very important concept and works in tandem with Validity. A guiding principle for psychology is that a test can be reliable but not valid for a particular purpose, however, a test cannot be valid if it is unreliable. Read more about Reliability... Assessment Validity