SURFing with Statistics New Zealand

1. SURFing with Statistics New Zealand Statistics Teachers' Day30 November 2007 Nathaniel Pihama and Deborah Brunning Statistics New Zealand

2. What you will see today • SURF for Schools • The Statistics New Zealand website • Table Builder ..and some ideas on how to use them!

3. The First SURF: a Synthetic Unit Record File for Schools

4. Overview: • Confidentiality – Big Picture • SURF??? • What is it? • How and why did we make a SURF? • What teachers and students can do with the SURF

5. What is a Unit Record File? Other names • Data set • Unit Record Data set • Microdata

6. Confidentiality Non release The pocket Safe Unsafe Useless Useful Raw dataset

7. Confidentialised Unit Record Files Confidentiality methods include: Categorical Data • Global recoding • Local recoding • Numerical Data • top/bottom coding, • capping, • rounding,

8. What is the SURF? • Data from 200 synthetic respondents. • Target population is those aged 15-45 in paid employment. • 7 variables

9. What does the SURF look like? The first 7 of 200 complete unit records

10. SURF- the variables

11. How to start SURFing? • The gender gap (Level 3 and 4) • Do more females have higher qualifications than males? • Is this different from how it was in the past? • Am I average? (Level 4) • What defines the average person? • Under pressure? (Level 5) • Are people who have never been married different from married people? • Equal Pay! (Level 6) • Are males and females paid equally? • Money for nothing (Level 7) • Investigating hours worked by employees in a company • Should I do a degree? (Level 8) • Investigation into whether getting a degree helps improve earning power http://www.stats.govt.nz/schools-corner

12. Task -Money for Nothing • A large company is concerned that it has too many employees who do not work a 40-hour week. • You have been hired to investigate the working patterns of the employees.

13. Further Analysis- Hours by Gender

14. Related variables – Hours by Marital Status

15. Related variables – Hours by Age Group

16. How ‘school friendly’ is SURF???? • SURF  Excel spreadsheet • Records are in random order • First 30 records could be used for manual data analysis • Use Excel How???????

17. An example of how to take a stratified sample Add Age_10 variable Add random numbers (then paste special as values)

18. Sort on random numbers Use filter – copy and paste records

19. Filter function

20. Pivot Tables

21. Pivot Tables

22. Box plots !!!! QUARTILE function SORT by Marital

23. Trend line in a scatter plot Good for quick visual check Provides equation & R-sq But no residuals Plot the data (XY scatter) (tidy plot up) Add Trendline Chart menu > Add trendline Options tab Regression and Residuals

24. Using Excel functions – SLOPE(), INTERCEPT(), RSQ() Copy cell ref into formula bar Regression and Residuals

25. Regression and Residuals - Easy to create predicted values and residuals (can copy formula and use $)

26. Regression and Residuals - Plot the residuals

27. The Statistics New Zealand Website

30. Stats NZ Products and Services • Schools Corner • Full of resources based on the curriculum. • Information releases – Hot Off the Press • Full of highlights, commentary, technical notes and tables! • New Zealand in Profile • Quick stats of New Zealand for 2007 • Analytical reports • Contain in depth analysis, background and technical information • Table Builder • Customisable tables of released survey data

35. Stats NZ Products and Services • Schools Corner • Full of resources based on the curriculum. • Information releases – Hot Off the Press • Full of highlights, commentary, technical notes and tables! • New Zealand in Profile • Quick stats of New Zealand for 2007 • Analytical reports • Contain in depth analysis, background and technical information • Table Builder • Customisable tables of released survey data

37. Stats NZ Products and Services • Schools Corner • Full of resources based on the curriculum. • Information releases – Hot Off the Press • Full of highlights, commentary, technical notes and tables! • New Zealand in Profile • Quick stats of New Zealand for 2007 • Analytical reports • Contain in depth analysis, background and technical information • Table Builder • Customisable tables of released survey data

39. Stats NZ Products and Services • Schools Corner • Full of resources based on the curriculum. • Information releases – Hot Off the Press • Full of highlights, commentary, technical notes and tables! • New Zealand in Profile • Quick stats of New Zealand for 2007 • Analytical reports • Contain in depth analysis, background and technical information • Table Builder • Customisable tables of released survey data

40. Battle for the ‘greener suburb’: an example of using case data from Table Builder

41. The statistical investigation cycle:(Wild and Pfannkuch, 1999) • Problem – the statement of the research questions • Plan – planning the procedures used to carry out the study • Data – the data collection process • Analysis – the summaries and analyses of the data to answer the questions posed • Conclusion – the conclusions about what has been learned.

42. Battle for the ‘greener suburb’:an example of using case data • Comparing the ‘traveling to work’ habits of area units within Auckland. • Which area has the ‘greener’ workers? • Walking / Running / Cycling • Public transport • Carpooling? • Working at home?

43. Battle for the ‘greener suburb’:where to find the data • We want a data source that contains information about modes of travel to work by area units. • Luckily, we have the 2006 Census of Population and Dwellings on Table Builder!