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Statistical Significance Testing

Statistical Significance Testing . Why do it? When to do it? How to it?. Testing is Important. Red shading is not statistically significant. Statements you might want to make. Estimate X is bigger than Y Estimate X this year is larger than X last year

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Statistical Significance Testing

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  1. Statistical Significance Testing Why do it? When to do it? How to it?

  2. Testing is Important Red shading is not statistically significant

  3. Statements you might want to make • Estimate X is bigger than Y • Estimate X this year is larger than X last year • Estimate X is smaller than Census 2000 value • State A has the highest Value

  4. Comparing SF3 or CTPP 2000 to current ACS Let’s do a test

  5. 1.Get the Margin of Error (MOE) from ACS 2. Calculate the Standard Error (SE) [SE = MOE / 1.645] 3. Solve for Z where A and B are the two estimates 4. If Z < -1.645 or Z > 1.645 Difference is Significant at 90% confidence How do I do a significance test?

  6. Obtaining Standard Error from MOE is Key • Sum or Difference of Estimates • Proportions and Percents • Means and Other Ratios There are different formulas Consult Appendix 3 in the “Compass for Understanding and Using ACS Data: What General Data Users Need to Know” Report Series. JUST CLICK HERE Where…. http://www.census.gov/acs/www/Downloads/ACSGeneralHandbook.pdf

  7. However HELP is Here PUSH BUTTON SIGNIFICANCE TESTER trbcensus.com/notes/StatisticalCalculationsMenu.xls

  8. But what if I am using 2000 non-ACS Data? Click Graphic and review Chapter 8 where do I get my SEs?

  9. You will need 2 things the Standard Error and Survey Design Factor Survey Design Factor X N = Size of publication area (population) Y = Estimate of characteristic

  10. Survey Design Factor Get Survey Design Factors from the Census 2000 SF3 Technical Documentation, Chapter 8 Table C. Mode to Work 1.4 1.2 0.9 0.7 http://www.census.gov/prod/cen2000/doc/tablec-fl.pdf Insert state abbreviation for specific state

  11. 5Y = 5* 126,540 632,700 1 - (Y/N) = 126,540 / 362,563 1- 0.3490152 0.6509848 N = Size of publication area (population = 362,563) Y = Estimate of characteristic SE = 641.7772 Solve for the unadjusted Standard Error (SE)

  12. Survey Design Factor X 126,540 / 362,563 = 35% SE = 641.777 Survey Design Factor at 35%-see slide 10 0.7 = Final Adjusted SE = 449 Adjust the SE by the Survey Design Factor

  13. Populate the adjusted SEs in your worksheet for 2000

  14. Calculate the ACS SE from the MOE Remember at 90% Significance Standard Error equals the MOE / 1.645

  15. A B Calculate Z and test is Z < -1.645 or Z > 1.645?

  16. Tempting is Z < -1.645 or Z > 1.645? Green is Significant This is NOT

  17. Try to do an exercise on your own?

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