Understanding distributions and data types

To comprehend some of the fundamental concepts of statistical analysis, it is important to appreciate the importance of the distribution of data points in the sample that is drawn to represent the population. Furthermore, one must understand the classification of data types. Data type and the distribution pattern of their values influence the choice of appropriate statistical tests. Emphasis will be placed on the normal, or Gaussian, distribution. This is an important distribution to understand because the assumption of this distribution underlies the use of many common statistical tests. The purpose of this article is to familiarize the clinician with some basic biostatistical concepts without delving into the statistical theory or debate associated with these concepts. There will be no presentation of mathematical formulas. The interested reader is referred to several texts, which will provide greater depth and rigor for those seeking additional knowledge. These texts were chosen specifically for their general readability and clarity and are referenced at the end of the article.