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.
â¢ As such, it must meet the requirements of any good instrument: â Validityâ Reliabilityâ Accuracy Validity â¢ Validity is the extent to which a test measures what it is intended to measure. â¢ Many ways of assessing validity exist.