Determination of fluid category 2. Water in fluid category 1 whose aesthetic quality is impaired owing to: 1  a change in its temperature; or. 2  the presence of substances or organisms causing a change in its taste, odour or appearance, including water in a hot water distribution system.
Credibility is defined as the quality or power of inspiring belief. Credible sources, therefore, must be reliable sources that provide information that one can believe to be true. It is important to use credible sources in an academic research paper because your audience will expect you to have backed up your assertions with credible evidence.
A key concept relevant to a discussion of research methodology is that of validity. When an individual asks, Is this study valid?, they are questioning the validity of at least one aspect of the study. There are four types of validity that can be discussed in relation to research and statistics.