Instrumentation in neonatal research: commonly used statistics

Nurse researchers share one common characteristic: They all use statistical tests to provide the answers they are seeking. For others to correctly interpret research, it is important to understand what choices of tests are available and why a test was used. As nursing becomes more sophisticated in the research arena, the ability to read, interpret, and critique reported research findings becomes an important component of professional practice. This month's column contains a description of commonly used statistical tests. Researchers are often interested in differences between groups and relationships between variables. Examples of these two types of research are provided to illustrate use of the various tests. One common part of statistical tests examining differences between groups is the number of degrees of freedom. Degrees of freedom are usually defined as the number of observations (number of subjects or categories) minus the number of limitations placed on those observations. Examples of this concept are provided throughout the pertinent tests.