FPL Statistics Unit Services Brochure

FS-FPL-4724 - Statistical Methods in Wood and Fiber Research

Statistical Services at the Forest Products Laboratory

1. Introduction

The Statistics Unit provides professional support to FPL personnel that need assistance with designing experiments, analyzing data, mathematical modeling, using computers for data analysis, and summarizing experimental results through graphical displays of data. This support is free for all Forest Service funded activities and free to any cooperative activities with limited funding. The mission of the Statistics Unit as defined in its Research Work Unit Description is:

To enhance the integrity and efficiency of the Forest Products Laboratory's research efforts through the development, evaluation, and promotion of modern statistical methods.

With this brochure, we hope to introduce FPL employees to the services available from the Statistics Unit, explain how these services can be obtained, and encourage employees to use them. We also want to emphasize the importance of consulting with statisticians early in the research cycle.

2. Support Activities

The support activities provided by the Statistics Unit can be broadly classified into three categories -- (1) traditional statistical support, which includes experiment design and data analysis, (2) mathematical and computing support, and (3) in-depth collaborative research with FPL personnel.

2.1 Traditional Statistical Support

The Statistics Unit provides traditional statistical support to FPL personnel that includes helping them design experiments, analyze data from experiments, and present results of experiments in publications and presentations. In addition, the Statistics Unit provides technical review of study plans and manuscripts. Members of the unit will even help write sections of study plans or manuscripts if needed. The Statistics Unit provides guidance to FPL personnel on the statistical aspects of Total Quality Management, Good Laboratory Practices, Quality Control, and Quality Assurance. In general, statistical support is available for any aspect of the research process. Probably the most important support the Statistics Unit provides is in design of experiments, which is discussed in more detail later.

2.2 Mathematical and Computing Support

The members of the Statistics Unit have expertise in areas other than pure statistics and are quite willing to share that expertise. In the past, we have provided support in each of the following areas:

2.3 Research Support

Research efforts by members of the Statistics Unit usually fall into two major categories, collaborative research and research in statistical methodology. In collaborative research, the statistician is an integral part of a research program requiring extensive statistical input. Research in statistical methodology is aimed at both developing new statistical procedures and evaluating existing statistical procedures when either is needed by research programs at FPL. Early involvement of the Statistics Unit in research studies is critical to efficient design of experiments and recognizing situations where a research support role might benefit the research program.

3. Statistical Support in Planning Research and Analyzing Results

The Statistics Unit offers substantial statistical support in experiment design, developing study plans, and analyzing and summarizing experimental results.

3.1 Design Of Experiments

This is probably the area in which statisticians can do the most to contribute to an efficient research program, and it is also our least utilized service. An hour or two spent with a statistician at the beginning of a project can prevent a great deal of heartache at the end of the project. Statisticians are trained to ask and help scientists answer a series of important and often overlooked questions:

We strongly encourage scientists to stop by and discuss their study plans with us while they are still being formulated.

3.2 Study Plan Guide

Members of the Statistics Unit are available to help write any aspect of a study plan where their expertise would help in the planning process. The Statistics Unit has a suggested framework for a study plan available to scientists who would like a guide. As an aid to the formulation of any study plan, we suggest that the following questions be addressed:

  1. What are the objectives of the study?

  2. What is the target population?

  3. What are the treatments, and what constitutes a control in the study?

  4. What are the experimental units going to be? Are we getting true replicates, or are we subsampling? How do we allocate treatments to the experimental units?

  5. What are the important covariates? (for example, time, temperature, relative humidity, specific gravity, ...) How do we intend to account for the effects of the covariates? Randomize? Block? Measure and include in an analysis of covariance?

  6. What is the justification of the proposed sample sizes?

  7. How are the data to be collected, entered, cleaned up, analyzed, and archived? What packages will be used to analyze the data? On what machines? By whom? How will the analyses be summarized and presented? Will the analyses meet the objectives of the study? Will the data be merged into an existing database, and is all the relevant information being collected to incorporate it into an existing database?

3.3 Data Analysis

Today, with the universal availability of microcomputers and statistical packages, many scientists like to do their own analyses. This is certainly a good idea for at least the initial stages of an analysis; a scientist has to get her/his hands dirty in the data to really get a feel for what is going on. There are circumstances, however, when a scientist might prefer to have the Statistics Unit assist in the analysis. The members of the Statistics Unit have access to powerful computer workstations and state-of-the-art statistical packages such as S-Plus and SAS. They also have expertise in writing custom FORTRAN, Perl, Java, C, and Pascal programs and in specialized computer graphics. Given a massive data set or a complex and potentially messy data analysis (lots of outliers, missing data, nonlinear models, ...), a scientist might wish to work with the Statistics Unit on the analysis.

4. Obtaining Services

Currently, a scientist may contact any member of the Statistics Unit to set up a meeting. Current telephone numbers for members of the unit are:

James Evans 608-231-9332
Cherilyn Hatfield 608-231-9334
Vicki Herian 608-231-9347
Patricia Lebow 608-231-9331
Steve Verrill 608-231-9375

[Forest Service] [Forest Products Lab] [FPL Statistics Unit]

We welcome your comments and suggestions.

This page was last modified on 4/30/03.