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Using Statistics To Make Inferences 5

Using Statistics To Make Inferences 5. Summary   Graphical presentation of data Goals To review graphical methods covered in semester 1 applied to real data Practical To examine the Vuyanich data, what tests might be appropriate?. 1. Skip to examples. Wednesday, 15 October 2014 1:19 AM.

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Using Statistics To Make Inferences 5

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  1. Using Statistics To Make Inferences 5 Summary   Graphical presentation of data Goals To review graphical methods covered in semester 1 applied to real data Practical To examine the Vuyanich data, what tests might be appropriate? 1 Skip to examples Wednesday, 15 October 20141:19 AM

  2. Background 723 F.2d 1195, Vuyanich v. Republic Nat. Bank of Dallas Joan Vuyanich began working as an agent contact clerk in Republic National Bank's ... Shortly thereafter, her supervisor told Vuyanich she should resign. ... 2

  3. Background Joan Vuyanich began working as an agent contact clerk in Republic National Bank's Money Order Department on April 29, 1969. She was the only black employee in that department. Shortly after beginning her job, she began having problems with two white female co-workers. She complained to her supervisors, and the situation was temporarily rectified. 3

  4. Background On June 29, 1969, Vuyanich married a white male. One month later, her supervisors met her husband. Shortly thereafter, her supervisor told Vuyanich she should resign. The supervisor gave as reasons her clashes with her co-workers, her complaints about her workload, and her not being suitable for the job. When Vuyanich inquired about a transfer, her supervisor replied that she probably did not need a job since her husband was white. Vuyanich was discharged on July 28, 1969. 4

  5. Background Less than two weeks later, Vuyanich filed a race discrimination charge against the Bank with the Equal Employment Opportunity Commission. She alleged a violation of Title VII of the Civil Rights Act of 1964, 42 U.S.C. Secs. 2000e to 2000e-17. The EEOC issued a finding that a reasonable basis existed to believe that a Title VII violation may have occurred. Conciliation efforts were unsuccessful, and the EEOC issued a statutory right-to-sue letter. On March 22, 1973, Vuyanich filed suit in the district court. 5

  6. Bank Employee Survey Information on 474 employees hired by a midwestern bank between 1969 and 1971. Created for an Equal Employment Opportunity (EEO) court case involving wage discrimination, the file includes salary, job category and several other human resource variables. 6

  7. Questionnaire Whats missing? 7

  8. Data The key claimant was Vuyanich, you will find further details on the web. Some typical data 8

  9. Categories 9 Whats missing?

  10. Charts Always look at your data first. Are charts a good idea? We will concentrate on “sex” for the charts. You can repeat this analysis or perform similar calculations for “minority”. 10

  11. Bar Chart 11

  12. Or? Tally for Discrete Variables: SEX SEX Count Percent female 216 45.57 male 258 54.43 N= 474 12

  13. Pie Chart 13

  14. Histogram 14

  15. Histogram This is still an area of active research! Shimazaki, Hideaki and Shinomoto, Shigeru 2007 “A method for selecting the bin size of a time histogram” Neural Computation 19(6) 1503-1527 DOI - Digital Object Identifier System Rudemo, M 1982 “Empirical Choice Of Histograms And Kernel Density Estimators” Scandinavian Journal Of Statistics 9(2) 65-78 Sturges, H. A. 1926 “The choice of a class interval” Journal of the American Statistical Association 21(153) 65-66 Software for calculating kernel densities 15

  16. Cumulative Frequency Polygon - Ogive 16

  17. Boxplot Outlier Minimum Lower Quartile Median Upper Quartile Maximum Upper Quartile Q3 Upper Limit Q3 + 1.5 (Q3-Q1) Median Lower Quartile Q1 Lower Limit Q1 - 1.5 (Q3-Q1) Inter Quartile Range Q3 – Q1 17

  18. Boxplot This is still an area of active research! Christopher Bruffaerts, Vincenzo Verardi, Catherine Vermandele, 2014 “A generalized boxplot for skewed and heavy-tailed distributions” Statistics & Probability Letters, ISSN 0167-7152. Journal or DOI - Digital Object Identifier System 18

  19. Boxplot 19

  20. Dotplot 20

  21. Descriptive Statistics Descriptive Statistics: SALNOW Variable SEX N N* Mean SE Mean StDev Minimum SALNOW female 216 0 10413 206 3023 6300 male 258 0 16577 486 7800 7860 Variable SEX Q1 Median Q3 Maximum SALNOW female 8595 9720 11400 23250 male 11220 13140 20290 54000 21

  22. Tables Tabulated statistics: SEX, JOBCAT Rows: SEX Columns: JOBCAT 1 2 3 4 5 6 7 All female 117 89 0 7 2 1 0 216 male 110 47 27 34 30 4 6 258 All 227 136 27 41 32 5 6 474 Cell Contents: Count 22

  23. Or A Plot? 23

  24. Or A Plot? 24

  25. What variables might we test? Current salary versus Minority Beginning salary versus Minority Salary rise versus Minority 25

  26. What variables might we test? Relative Salary rise versus Minority 26

  27. What variables might we test? Relative Salary rise versus Minority 27

  28. What other factor might be relevant? Salary rise given Job seniority versus Minority What about Sex? 28

  29. Practical 5 This material is available from the module web page. http://www.staff.ncl.ac.uk/mike.cox Module Web Page 29

  30. Practical 5 This material for the practical is available. Instructions for the practical Practical 5 Material for the practical Practical 5 30

  31. There are three kinds of Lies; Lies, Damned Lies and Statistics Mark Twain or Benjamin Disraeli! actually Leonard Henry Courtney 1832 to 1918 31

  32. How Food Scares Galloped Across Europe Financial Times February 11, 2013 By Joshua Chaffin in Brussels and Hugh Carnegy in Paris 32

  33. How Food Scares Galloped Across Europe 33

  34. How Food Scares Galloped Across Europe 34

  35. Bullet Holes • The bullet holes were all over the place on the R.A.F. planes -- in the wings and the fuselage, and seemingly distributed randomly on the undersides. So, where did the R.A.F. mathematician recommend extra armour, to save future missions? • "A method of estimating plane vulnerability based on damage of survivors" by Abraham Wald 35

  36. Bullet Holes 36

  37. Bullet Holes 37

  38. Singleton BoomSingleton boom ... the number of single-person households has doubled in the last 30 years - The Sun, 13 July, 2004 Critique! J J J J J J j 38

  39. Singleton BoomSingleton boom ... the number of single-person households has doubled in the last 30 years - The Sun, 13 July, 2004 39

  40. Polls Need Careful Reading to Work Out What's Going On The Times October 26, 2006 40

  41. Polls Need Careful Reading to Work Out What's Going On The Times October 26, 2006 41

  42. Age Structure …… ……… …………… Age Structure Of College Enrolment American Education Magazine Why reflect? Why colour? Why 3D? How much data? 42

  43. Heavy Drinking Kills Twice As Many People As In 1991The Times November 08, 2006 43

  44. Heavy Drinking Kills Twice As Many People As In 1991 The Times November 08, 2006 44

  45. Pie Chart www.bbc.co.uk/skillswise/ 2004 45

  46. Pie Chart 46

  47. Online Casinos 'Used To Launder Cash' The Times November 01, 2006 47

  48. Online Casinos 'Used To Launder Cash' The Times November 01, 2006 48

  49. Online Casinos 'Used To Launder Cash' The Times November 01, 2006 49

  50. Online Casinos 'Used To Launder Cash' The Times November 01, 2006 50

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