Basic statistical concepts in nutrition research.

Statistical principles are used in nutrition research to plan and conduct research studies and to answer research questions. This article describes general statistical concepts and provides some guidelines to assist in the interpretation of research literature. Prospective and retrospective study designs used in nutrition research are presented as well as the advantages and disadvantages of each of the study designs. Descriptive statistics used to summarize data and graphical tools used to display the shape of the distribution of a set of data guide nutrition support professionals to select appropriate statistical tests. Fundamental topics of statistics, including power analysis and sample size, confidence intervals and hypothesis testing, and analysis of variance and regression, are also reviewed. The article emphasizes the importance of effective collaboration with statisticians at an early stage of the research study to avoid potential pitfalls associated with improper utilization of statistical methods.