Statistical Consulting Service
Information Technology Services and the Department of Statistics jointly support the Statistical Consulting Service (SCS) at North Dakota State University. This service is available to all faculty, staff, and students at North Dakota University System institutions, usually at no charge.
Statistical Consulting offices are located in IACC 210. Consultants (one full time staff member plus Statistics Department graduate students) are available by appointment and during office hours, usually 10:00-4:00 Monday through Friday.
The Statistical Consulting Service (SCS) currently provides assistance to clients at various stages of the research process.
Planning Phase. SCS Consultants will discuss:
- your research goals and assist you in identifying aspects of your research that may benefit from the application of statistical principles
- the design of experiments; e.g., identification of response variables, factors, and type of statistical design appropriate for your research.
- mechanisms for collecting, entering (e.g., Excel) and handling data prior to statistical analysis.
Data Organization and Analysis Phase. Consultants will:
- assist in managing and processing data.
- suggest appropriate statistical methods for data analysis.
- obtain data from client, perform appropriate statistical analyses.
Communication of Results Phase. SCS Consultants will:
- recommend methods of data presentation, portrayal of results.
- facilitate graphical display of data by pre-processing your data and generating transportable output such as GIF or PNG.
- generate presentation graphics for clients as needed.
Most of our consulting work is done using SAS. We also have experience with SPSS (Curt), JMP (Curt) and R (Statistics Graduate Students).
Our experience with statistical methods is fairly broad, but certain methods comprise a lot of our consulting efforts. These include:
- regression (both linear and nonlinear)
- ANOVA including various specializations such as repeated measures and mixed models
- discrete data analysis methods (e.g., frequency tables with chi-square tests)
- multivariate methods
Recent years have seen increases in the use of methods such as Generalized Linear Mixed Models (GLMMs), resampling techniques (bootstrapping, permutation tests and Monte Carlo methods) and graphical methods/visualization techniques. If you are interested in assistance with areas not listed, feel free to check with us anyway -- we have used many other methods not listed and we are always looking to broaden our experiences.
Members of the SCS are interested in developing longer term collaborative work with researchers in a wide variety of disciplines. Examples of such projects include but are not limited to:
- reviewing the exposition of statistical results in proposals and manuscripts.
- previously this has included reviewing papers by members of the following departments: Pharmacy, Zoology, Plant Pathology, Agricultural and Biosystems Engineering, Business, and Cereal Science.
- contributing to collaborative projects throughout the duration of the research process. This could include visiting the laboratory or research site to better understand the research project.
- occasional involvement in outreach projects with external organizations.
- in recent years, we have collaborated on the Explorers Survey with the regional office of the Boy Scouts of America.
Publications in which members of Statistical Consulting have been included as coauthors are listed below. These represent collaborations where the primary subject matter researchers felt that the statistical contribution was significant enough to merit coauthorship. We agree to coauthorship only if we believe we have contributed significantly to the content and the primary authors offer to include us. There are many other instances where our efforts have been acknowledged but not at the coauthorship level.
- Knutson EM, Richman DB and Doetkott C. 2010.
Arboreal Spider Ecology on Saltcedar (Tamarix) at Big Spring, Howard County, Texas.
Southwestern Entomologist V35(4) 513-523.
- Bhattacharjee P, Panigrahi S, Lin D, Logue CM, Sherwood JS, Doetkott C, and Marchello M. 2010.
Study of Headspace Gases Associated with Salmonella Contamination of Sterile Beef in Vials Using HS-SPME/GC-MS.
Transactions of the American Society of Agricultural and Biological Engineers 53(1):173-181.
- Johnson TJ, Logue CM, Wannemuehler Y, Kariyawasam S, Doetkott C, DebRoy C, White DG, Nolan LK. 2009.
Examination of the source and extended virulence genotypes of Escherichia coli contaminating retail poultry meat.
Foodborne Pathog Dis. 2009 Jul-Aug;6(6):657-67.
- Balasubramanian S, Panigrahi S, Logue CM, Doetkott C, Marchello M, and Sherwood JS. 2008.
Independent component analysis-processed electronic nose data for predicting Salmonella typhimurium populations in contaminated beef.
Food Control 19(3): 236-246.
- Johnson TJ, Wannemuehler Y, Doetkott C, Johnson SJ, Rosenberger SC, and Nolan LK. 2008.
Identification of Minimal Predictors of Avian Pathogenic Escherichia coli (APEC) Virulence for Use as a Rapid Diagnostic Tool.
J Clin Microbiology 46(12): 3987-3996.
- Johnson TJ, Wannemuehler Y, Johnson SJ, Stell AL, Doetkott C, Johnson JR, Kim KS, Spanjaard L, and Nolan LK. 2008.
Comparison of Extraintestinal Pathogenic Escherichia coli Strains from Human and Avian Sources Reveals a Mixed Subset Representing Potential Zoonotic Pathogens.
Applied and Envir. Micro 74(22): 7043-7050.
- Thorsness JL, Sherwood JS, Danzeisen GT, Doetkott C, and Logue CM. 2008.
Baseline Campylobacter Prevalence at a New Turkey Production Facility in North Dakota.
J Food Protection 71(11): 2295-2300.
- Nde CW, Fakhr MK, Doetkott C, and Logue CM. 2008.
An Evaluation of Conventional Culture, invA PCR, and the Real-Time PCR iQ-Check Kit as Detection Tools for Salmonella in Naturally Contaminated Premarket and Retail Turkey.
J Food Protection 71(2): 386-391.
- Lynne AM, Skyberg JA, Logue CM, Doetkott C, Foley SL, and Nolan LK. 2007.
Characterization of a Series of Transconjugant Mutants of an Avian Pathogenic Escherichia Coli Isolate for Resistance to Serum Complement.
Avian Dis. 51(3): 771-776.
- Helms TC, and Doetkott, C. 2007.
An Educational Software for Simulating Sample Size of Molecular Marker Experiments.
Journal of Natural Resources and Life Sciences Education 36:53-57.
- Johnson TJ, Wannemuehler YM, Johnson SJ, White DG, Doetkott C, and Nolan LK. 2007.
Plasmid Replicon Typing of Commensal and Pathogenic Escherichia coli Isolates.
Applied and Envir. Micro. 73(6):1976-1983.
- Johnson TJ, Kariyawasam S, Wannemuehler Y, Mangiamele P, Johnson SJ, Doetkott C, Skyberg JA, Lynne AM, Johnson JR and Nolan LK. 2007.
Genome Sequence of Avian Pathogenic Escherichia coli Strain O1:K1:H7 Shares Strong Similarities with Human ExPEC Genomes.
J Bact. 2007 189: 3228-3236.
- Helms TC, and Doetkott C. 2007.
Educational Software for Mapping Quantitative Trait Loci (QTL).
Journal of Natural Resources and Life Sciences Education 36:6-10.
- Skyberg JA, Siek KE, Doetkott C, and Nolan LK. 2007.
Biofilm formation by Avian Escherichia coli in Relation to Media, Source and Phylogeny.
J Applied Microbiology 102: 548-554.
- Boetel MA, Dregseth RJ, Schroeder AJ and Doetkott C. 2006.
Conventional and Alternative Placement of Soil Insecticides to Control Sugarbeet Root Maggot (Diptera: Ulidiidae) Larvae.
J. Sugar Beet Research 43(3): 47-63.
- Welch J, Webb M, Koo J, and Doetkott C. 2006.
Factors Associated with Epoetin Response: Drug Utilization Evaluation.
Pharmacy and Therapeutics 31(9): 524-529.
- Heilmann LJ, Nitzan N, Johnson DA, Pasche JS, Doetkott C, and Gudmestad NC. 2006.
Genetic Variability in the Potato Pathogen Colletotrichum coccodes as Determined by Amplified Fragment Length Polymorphism and Vegetative Compatibility Group Analysis.
Phytopathology 96: 1097-1107.
- Nde CW, Sherwood JS, Doetkott C. and Logue CM. 2006.
Prevalence and Molecular Profiles of Salmonella Collected at a Commercial Turkey Processing Plant.
J. of Food Protection 69:1794-1801.
- Logue CM, Sherwood JS and C Doetkott. 2006.
Growth Studies of Plasmid Bearing and Plasmid Cured Yersinia enterocolitica GER O:3 in the Presence of Cefsulodin, Irgasan and Novobiocin at 25 and 37 C.
J. Applied Microbiology 100:1299-1306.
- Olah PA, Doetkott C, Fakhr MK, and Logue CM. 2006.
Prevalence of the Campylobacter Multi-drug Efflux Pump (CmeABC) in Campylobacter spp. Isolated from Freshly Processed Turkeys.
Food Microbiology 23:453-460.
- Rodriguez-Siek K, Giddings CW, Doetkott C, Johnson TJ, Fakhr MK and Nolan LK. 2005.
Comparison of Escherichia coli Isolates Implicated in Human Urinary Tract Infection and Avian Colibacillosis.
- Johnson TJ, Siek K, Skyberg J, Doetkott C, and Nolan LK. 2005.
Plasmid-Linked Virulence Factors among Avian Pathogenic Escherichia coli.
Plasmid Biology 2004: International Symposium on Molecular Biology of Plasmids and Other Mobile Genetic Elements, Kanoni, Corfu, Greece, September 2004. Plasmid 53: 23-96.
- Rodriguez-Siek K, Giddings CW, Doetkott C, Johnson TJ, and Nolan LK. 2005.
Characterizing the APEC Pathotype.
Vet. Res. 36:241-256.
- Ewert D, Wheeler B, Doetkott C, Ionan C, Pantalos G, and Koenig SC. 2004.
The Effect of Heart Rate, Preload, and Afterload on the Viscoelastic Properties of the Swine Myocardium.
Annals Biomed.l Eng. 32:1211-1222.
- Balasubramanian S, Panigrahi S, Logue C, Marchello M, Doetkott C, Gu H, and Nolan LK. 2004.
Spoilage Identification of Beef Using an Electronic Nose System.
Trans Am Soc Agric Eng 47: 1625-1633.
- Schnell CA, Louis KS and Doetkott . 2003.
The First-year Seminar as a Means of Improving College Graduation Rates.
Journal of the First-Year Experience and Students in Transition. Vol. 15(1) 53-75.
- Schnell CA and Doetkott CD. 2003.
First Year Seminars Produce Long-term Impact.
Journal of College Student Retention. Vol. 4(4) 377-391.
- Jeffrey JS, Nolan LK, Tonooka KH, Wolfe S, Giddings CW, Horne SM, Foley SL, Lynne AM, Ebert JO, Elijah LM, Bjorklund G, Pfaff-McDonough SJ, Singer RS, and Doetkott C. 2002.
Virulence Factors of Escherichia coli from Cellulitis or Colisepticemia Lesions in Chickens.
Avian Dis. 46:48-52.
- Nolan LK, Giddings CW, Horne SM, Doetkott C, Gibbs PS, Wooley RE, and Foley SL. 2002.
Complement Resistance, as Determined by Viable Count and Flow Cytometric Methods, and its Association with the Presence of iss and the Virulence of Avian Escherichia coli.
Avian Dis. 46: 1-8.
- Finck KM, Doetkott C and Miller D. 2001.
Clinical Impact of Interlaboratory Variation in International Normalized Ratio Determinations.
Am J Health-Syst Pharm 58(8), 684-88.
- Petermann S R, Doetkott C and Rust L. 2001.
Elastase deficiency phenotype of Psuedomonas aeruginosa Canine Otitis Externa Isolates.
Clin. Diag. Lab. Immun. 8(3):632-636.
- Pfaff-McDonough S, Horne S, Nolan LK, Giddings C, Doetkott C, and Smith, MH. 2000.
Complement-Resistance-Related Traits among Escherichia coli Isolates from Apparently Healthy Birds and Birds with Colibacillosis.
Avian Diseases 44:23-33.
- Rayas-Duarte P, Majewska K, and Doetkott C. 1998.
Effect of Extrusion Process Parameters on the Quality of Buckwheat Flour Mixes.
Cereal Chemistry 75(3):338-345.
- Debbouz A and Doetkott C. 1996.
Effect of Process Variables on Spaghetti Quality.
Cereal Chemistry 73(6):672-676.
Statistical Consulting Office: IACC 210B, 701-231-1077
Curt Doetkott: IACC 210H, 701-231-7031