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.
A reliable instrument produces consistent results regardless of the setting, yet reliability does not ensure accuracy or validity. Validity refers to an instrumentâs capacity to accurately measure what the researcher intended to measure. Reliability must be accompanied with validity regarding an instrument worthy of use in conducting doctoral research. A few simple examples help explain the meaning of reliability and validity.