Turning data into knowledge to solve real world problems

1. Turning data into knowledge to solve real world problems Christopher R. Bilder, Ph.D. Department of Statistics University of Nebraska-Lincoln www.chrisbilder.com www.chrisbilder.com

2. 11 years ago… • The year is 1993 • Pearl Jam records second CD, Vs., • Daughter, Go, Elderly Woman Behind the Counter in a Small Town • Bill Clinton was inaugurated as the 41st president • Movies • Jurassic Park • Sleepless in Seattle • Husker football • 1993 season went undefeated • Math 4750 - Introduction to Probability and Statistics II • 4-5:15PMTuesdays and Thursdays in DSC 164   • Dr. Stephens www.chrisbilder.com

3. 11 years ago… • Actuarial Science! • Planned to be an actuary when I started college • Internship at National Indemnity Company at 32nd and Harney • Passed 4 exams under old system • Wanted to go on to graduate school • Math? • Actuarial Science? • Hypothesis testing in Math 4750 • Use for decision making! • Scientifically prove a hypothesis or statement • Go to graduate school for statistics! • 1994 received BS in Mathematics with pre-actuarial science minor from UNO www.chrisbilder.com

4. After UNO • Went on to graduate school for statistics • MS 1996 from Kansas State University • PhD 2000 from Kansas State University • Internships at INEEL in Idaho and pharmaceutical company in Kansas City • Consult with students and professors in sociology, agriculture,… • Taught courses like Statistical Methods I and II (STAT 3000 and 3010) • Assistant Professor at Oklahoma State University • Department of Statistics • 2000-2003 • Assistant Professor at UNL • NEW Department of Statistics • 2003-present www.chrisbilder.com

5. Purpose • Tell you a little about statistics • Statistics is mainly a graduate discipline • Most statisticians have undergraduate degrees in math • Turning data into knowledge to solve real world problems • 3 actual examples that come from my teaching and research • About statistics at UNL • Website (www.chrisbilder.com/statistics) for more information www.chrisbilder.com

6. Grocery store prices • Undergraduate teaching example for a course like STAT 3000 for math and non-math majors • How could you determine which grocery store, Super Wal-Mart or Albertson’s, has lower average prices? • Paired or dependent two sample hypothesis test for Wal-Mart - Albertsons • Sample the same items at each store www.chrisbilder.com

7. Grocery store prices • Undergraduate teaching example for a course like STAT 3000 for math and non-math majors • How could you determine which grocery store, Dillon’s or Food-4-Less in Manhattan, KS, has lower average prices? • Paired or dependent two sample hypothesis test for Dillon’s - Food-4-Less • Sample the same items at each store • Only cereals from Fall 1998 • Possible problems described later www.chrisbilder.com

8. Grocery store prices • Sample: www.chrisbilder.com

9. Grocery store prices • Do you think there are mean differences? 75% 50% 25% www.chrisbilder.com

10. Grocery store prices • Paired two sample hypothesis test • Ho:Dillon’s - Food-4-Less=0Ha:Dillon’s - Food-4-Less0 • t = 4.77, p-value = 0.0002, 95% C.I.: 0.1644 < Dillon’s - Food-4-Less < 0.4274 • Reject equal mean prices • If price was the only consideration, what store should one shop at? • Assumptions • Are prices and selection at these two stores indicative of all stores? • Normal populations • The sample was taken in 1998; what about now? • Finite populations www.chrisbilder.com

11. Placekicking • MS report – applying statistics to new problems or investigating new methodology • 120 page book! • Reduced version published in Chance in 1998 • Find a model to estimate the probability of successfor placekicks in the NFL • Video • January 7, 1996 • Playoff game • Indianapolis Colts 10Kansas City Chiefs 7 • Lin Elliott of KC will attempt a 42 yard field goal to tie the game and send it into overtime www.chrisbilder.com

12. Placekicking • What factors affect the probability of success for NFL placekicks? • Distance • Pressure – How do you quantitatively measure? • Wind • Grass vs. artificial turf • Collected data >1,700 placekicks during the 1995 NFL season • Find the best logistic regression model of the form where p is the probability of success xi for i=1,…,k are independent variables i measures the effect of xi on p for i=1,…,k www.chrisbilder.com

13. Placekicking • The i’s are parameters which are estimated through maximum likelihood estimation • Estimated model • Change: lead change = 1, non-lead change = 0 • Distance: distance in yards • PAT: point after touchdown = 1, field goal = 0 • Wind: windy (speed > 15 MPH) = 1, non-windy = 0 • What is the estimated probability of success for Elliott’s field goal? • Conditions: • Estimated probability of success: • 90% confidence interval for probability of success: 0.6298 < p < 0.7402 www.chrisbilder.com

14. Estimated probability of success for a field goal (PAT=0) 0.685 42 www.chrisbilder.com

15. Placekicking • UNL Department of Statistics developing statistics in sports specialty • Dr. David Marx • Works with the UNL athletic department • January 10, 2004 Omaha World Herald article about his work the men’s basketball team (available at www.chrisbilder.com/statistics) • His students this semester have worked with NASCAR, Lincoln SE women’s high school soccer team, and Tendu, Inc. (baseball software company). • Myself • Placekicking • Modeling 64-team NCAA tournaments www.chrisbilder.com

16. Hepatitis C prevalence  + or - + or - + or - + or - + or - + or - • MS/PhD research – forwarding statistical theory and methodology • Hepatitis C • Viral infection that causes cirrhosis and cancer of the liver • Screening blood donors is important to prevent transmission • Questions: • How can blood be screened in a cost effective and timely manner? • What proportion of people is inflicted with Hepatitis C in a population? • Individual testing • Each blood sample is tested individually • Problems: • Costly • Time www.chrisbilder.com

17. Hepatitis C prevalence + or - + or - + or -  • Group testing • Pool the blood samples together to form n groups of size s • If the GROUP sample is negative, then all s people do not have the disease • If the GROUP sample is positive, then at least ONE of the s people have the disease • Strategy works well when prevalence of a disease is small • Dorfman (1943) – first used to test members of the military for disease Group 1 Group 2 Group n www.chrisbilder.com

18. Hepatitis C prevalence Brown planthopper Whitebacked planthopper • Multiple vector transfer designs • Swallow (Phytopathology, 1985) • Want to estimate the probability a insect vector transfers a pathogen (virus, bacteria, etc.) to a plant www.chrisbilder.com

19. Why statistics? • Statistics is used in many diverse areas! • Statistics is the “science of science” • Florence Nightingale quote: the most important science in the whole world: for upon it depends the practical application of every other science and of every art: the one science essential to all political and social administration, all education, all organization based on experience, for it only gives results of our experience. • I hope you have an interest to take more statistics courses • UNO • Graduate school in statistics or non-statistics programs • Of course, I want you to consider coming to UNL! www.chrisbilder.com

20. Statistics at UNL • Facts • July 1, 2003 formed • 11 faculty + 2 more in 2004 • No undergraduate major • 40+ MS and PhD graduate students (most MS) • Strong commitment from administration • Hardin Hall on East Campus www.chrisbilder.com

21. Statistics at UNL 33rd st. Department of Statistics www.chrisbilder.com

22. Statistics at UNL • Background of new students • A few statistics courses – like UNOMATH 4740 and 4750 • Statistics is mainly a graduate discipline • Majority have math degrees • Recommendation for UNO classes (I took the classes in yellow) • Math 4740 and 4750 Intro. to Probability and Statistics I and II • Math 3300 Numerical Methods • Math 4760 Topics in Modeling • Math 4050 Linear Algebra • Math 4230 and 4240 Mathematical Analysis I and II • Helpful if you plan to go on for a PhD • Stat 3000 and 3010 Statistical Methods I and II www.chrisbilder.com

23. Statistics at UNL • Recommendation for UNO classes (continued) • Business administration course: 3140 Business Statistical Applications • Computer science programming courses • Information Systems & Quantative Analysis Department courses • 4150 Advanced Statistical Methods for IS&T • 8160 Applied Distribution Free Statistics • 8340 Applied Regression Analysis • 9120 Applied Experimental Design and Analysis • 9130 Applied Multivariate Analysis www.chrisbilder.com

24. Statistics at UNL • Assistantships • Work 16-20 hours a week • Teaching - $13K per school year + tuition (MS students) • Project Fulcrum grants - $30K per school year! • 6 statistics students over the past 3 years have received grant • Research - variable depending on grants • Statistics and non-statistics faculty grants • What makes us unique? • Consulting course and help desk • STAT 971 – Statistical Modeling • Statistics in sports and work with UNL athletic department • Consulting - All departments in the College of Agriculture and Natural Resources • Gallup Organization • Bioinformatics www.chrisbilder.com

25. Statistics at UNL • Where do statistics graduates work? • Pharmaceutical – Pfizer, Merck • Marketing – Target, Hallmark • Government research labs – INEEL, Los Alamos, Sandia, Argonne • Agriculture - Pioneer Hi-Bred • Consulting firms – Quintiles • Every statistics student that I have known has had a job offer before they graduated! • Salaries • Non-academic starting (2003 American Statistical Association survey) • Survey response rate was 23.5% by organizations surveyed • See salary surveys at the American Statistical Association’s website www.chrisbilder.com

26. Statistics at UNL • Applying for graduate school in statistics • Send out applications before end of fall semester • Apply to more than one school • Visit schools in fall or early spring • Assistantship offers usually first go out in March • 7th Annual UNL Regional Workshop in Mathematical Sciences • Statistics, Mathematics, and Computer Science departments • November 2004 • Friday afternoon & evening and Saturday morning • Speakers introducing statistics and jobs in statistics • FUNDING available! www.chrisbilder.com

27. Statistics at UNL • For more information… • E-mail me at cbilder3@unl.edu or chris@chrisbilder.com • Advice • Sit in on a class • Website: www.chrisbilder.com/statistics • This PowerPoint presentation • Links to • Introductory information about being a statistician • Jobs (including internships) • Salary information • List of all Departments of Statistics • Professional societies • MS and PhD course websites that myself and others teach • Newspaper and magazine articles about statistical applications www.chrisbilder.com