Statistical Handbook for Dental Science

Introduction

This handbook provides an introduction to statistical tools and methodologies commonly used in the field of dentistry and was developed after a survey of papers in the research area of dental materials. It attempts to strike a balance between quality of the statistical argumentation and the field-specific expectations and standards observed through this survey of papers. While the reader may wish to consult more in-depth presentations of statistical methods in many available textbooks, the goal of this website is to provide a concise handbook of the primary techniques used in the research area of dentistry with a focus on the ease of use to the researcher. To keep the handbook brief, the authors made several choices as to the information presented and the technical details to highlight for each methodology.

To help the dentistry researcher overcome the multitude and complexity of statistical methodologies, we provide the reader with several flowcharts that can guide the investigator in identifying the correct approach for the specific setting of their investigation. Using the navigation bar on the left, the reader can then open the section of the handbook that introduces this specific methodology and provides accessible explanations for employing the technique. Each topic also comes with field-specific examples from dentistry as well as practical advice for applying the statistical methodology. The reader who is perhaps unfamiliar with the intricacies of these statistical tools will find it useful to read examples within the specific scientific context of the field of dentistry. Since each statistical methodology has underlying assumptions that must be satisfied before the technique can be employed, we also offer an introduction to the topics of normality, independence and constant variance with field-specific examples and advice.

The handbook is also accompanied by code for the statistical language R for the principal statistical techniques outlined in this handbook. R is an open-source software that is commonly used by statisticians and researchers in both academic and commercial settings. The reader can download R for free at the Comprehensive R Archive Network. The R-code we provide for each statistical methodology can be used by the researcher on their own data by simply importing their spreadsheet into R. One advantage of using the software R is that the code can be modified using a multitude of available options to meet the user’s needs. A vast library of packages and examples for R-code is freely available online (see for example https://stackoverflow.com/). Moreover, R has the ability to produce high quality, publication-ready graphs that the reader can also customize. This website provides the R-code for the many methodologies and examples used in our handbook, and thus makes the programming aspect of a research project accessible to the user without extensive experience with R.

We hope the reader will find our concise handbook for the field of dentistry useful in navigating the multitude of choices as well as the complexities of statistical methodologies. For suggestions or questions about the handbook please email us at wyu@bridgew.edu.

Acknowledgments

The preparation of this handbook has been supported in part by a grant from the Center of Advancement of Research and Scholarship at Bridgewater State University.