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.
Test-Retest Reliability. Test-retest reliability is a measure of the consistency of a psychological test or assessment. This kind of reliability is used to determine the consistency of a test across time. Test-retest reliability is best used for things that are stable over time, such as intelligence.