Building Core Concepts with Computational Software Robert H. Carver Stonehill College Easton MA August 9, 2004 Core Concept Candidates Population Sample Variation Observation vs. Experiment Cross-section vs. longitudinal data Comparison Standardization Probability “Random” Random sampling “Error” August 9, 2004 Sampling error Statistical control Confidence Distribution Null hypothesis Association Causation Statistical significance vs. Practical significance Power Model JSM Toronto Session 154 2 Concepts for this segment Variation Statistical control Sampling Error August 9, 2004 JSM Toronto Session 154 3 ASQ on Statistical Thinking All work occurs in a system of interconnected processes Variation exists in all processes Understanding and reducing variation are keys to success August 9, 2004 JSM Toronto Session 154 4 A tale of continuous improvement… Wright 1904 Flyer over Huffman Prairie, Dayton OH August 9, 2004 JSM Toronto Session 154 5 Wilbur Wright on Control, 1901 “This inability to balance and steer still confronts students of the flying problem…. “When this one feature has been worked out, the age of flying machines will have arrived, for all other difficulties are of minor importance.” August 9, 2004 JSM Toronto Session 154 6 Variation: What’s up with that? August 9, 2004 JSM Toronto Session 154 7 Mean flight velocity Time Series Plot of VelMPH 90 80 70 VelMPH 60 50 40 30 20 10 0 1 August 9, 2004 9 18 27 36 45 54 Index JSM Toronto Session 154 63 72 81 8 Shape—velocity & distance Histogram of VelMPH Normal 35 Mean StDev N 30 29.50 11.83 68 20 Histogram of Distm 15 Normal 50 10 5 0 40 20 40 60 VelMPH 80 Frequency Frequency 25 30 20 10 0 August 9, 2004 -1000 JSM Toronto Session 154 0 1000 2000 Distm 3000 4000 9 5000 Comparison: assignable cause? Boxplot of VelMPH vs PILOT 90 80 70 VelMPH 60 50 40 30 20 10 0 OW WW PILOT August 9, 2004 JSM Toronto Session 154 10 Comparison: assignable cause? Boxplot of Distm vs Launch 5000 4000 Distm 3000 2000 1000 0 Rail August 9, 2004 Catapult Launch JSM Toronto Session 154 11 Control & shrinking variation Time Series Plot of VelMPH 90 80 70 VelMPH 60 50 40 30 20 10 0 1 August 9, 2004 9 18 27 36 45 54 Index JSM Toronto Session 154 63 72 81 12 Control I Chart of VelMPH 1 90 80 1 Individual Value 70 60 50 40 30 20 10 0 1 August 9, 2004 10 19 28 37 46 55 Observation JSM Toronto Session 154 64 73 82 13 Developing a feel for Sampling Error 10 Random Samples -- Velocity n = 10 from population of 68 flights 90 Mean Flight Velocity (mph) 80 70 60 50 40 30 29.5 20 10 0 Samp1 August 9, 2004 Samp2 Samp3 Samp4 Samp5 Samp6 Samp7 JSM Toronto Session 154 Samp8 Samp9 Samp10 14 Developing a feel for Sampling Error One-Sample T: Samp1, Samp2, Samp3, Samp4, Samp5, Samp6, Samp7, ... Variable Samp1 Samp2 Samp3 Samp4 Samp5 Samp6 Samp7 Samp8 Samp9 Samp10 N 10 10 10 10 10 10 10 10 10 10 August 9, 2004 Mean 26.1458 30.8669 23.8366 31.1267 28.7766 28.3671 22.2507 29.3899 28.8168 31.1217 StDev 7.0527 16.0146 8.6156 7.6951 8.6148 8.2640 9.6897 7.5919 11.0398 22.3381 SE Mean 2.2303 5.0643 2.7245 2.4334 2.7242 2.6133 3.0642 2.4008 3.4911 7.0639 JSM Toronto Session 154 95% (21.1006, (19.4107, (17.6734, (25.6220, (22.6139, (22.4554, (15.3191, (23.9590, (20.9194, (15.1420, CI 31.1910) 42.3231) 29.9998) 36.6315) 34.9393) 34.2788) 29.1823) 34.8208) 36.7142) 47.1014) 15 Guiding Principles Focus on reading the story in the data Rely on software to facilitate building the concepts Quick, interactive analysis to seize teachable moments Demonstration, discovery, iteration August 9, 2004 JSM Toronto Session 154 16 Sources American Statistical Association (2004). Curriculum Guidelines for Undergraduate Programs in Statistical Science. https://www.amstat.org/education Fisher, R.A. (1966). The Design of Experiments. (New York: Hafner) Garfield, J., Hogg, R., Schau, C., & Whittinghill, D. (2000). “Best Practices in Introductory Statistics,” draft position paper prepared for JSM 2000. Hoerl, R.W. & Snee, R.D. (2002). Statistical Thinking: Improving Business Performance. (Pacific Grove, CA: Duxbury) Jakab, P.L. & Young, R., eds. (2000). The Published Writings of Wilbur and Orville Wright. (Washington DC: Smithsonian) Kugler, C., Hagen, J. & Singer, F. (2003). “Teaching Statistical Thinking.” Journal of College Science Teaching, v32, No. 7, 434-439. McCarthy, P.J. (1957). Introduction to Statistical Reasoning (New York, McGraw-Hill) Moore, D.S. (1997). Statistics: Concepts and Controversies, 4th Ed. (New York: W.H. Freeman) Phillips, J. L. Jr. (1992). How to think about statistics. (New York: W.H. Freeman) Salsburg, D. (2002). The Lady Tasting Tea. (New York: Owl Books) Tukey, J.W. (1971). Exploratory Data Analysis. (Reading MA: Addison Wesley). U.S. Centennial of Flight Commission (2003). Flight log: Huffman prairie, 1904. http://www.centennialofflight.gov/chrono/log/1904HuffmanPrairie.htm Utts, J. M. )1999). Seeing Through Statistics, 2nd Ed. (Pacific Grove CA: Duxbury) Wallis, W. A. & Roberts, H. V. (1956). Statististics: A New Approach. (New York, Free Press.) Wright Redux Association (2001). Wright history. The Wright redux association. http://www.wrightredux.org/index.cfm?page=5 August 9, 2004 JSM Toronto Session 154 17 Contact Information Robert H. Carver Dept. of Business Administration Stonehill College Easton MA 02357 e-mail: rcarver@stonehill.edu Copies of slides and dataset available (after JSM) at: http://faculty.stonehill.edu/rcarver/index.htm August 9, 2004 JSM Toronto Session 154 18