1. 3 Three Common Errorsin statistical thinking

2. Overview Misleading bar charts Correlation and causation Two kinds of significance

3. Error 1 Misleading Bar Charts

4. Student Satisfaction Data Excerpt ? Can you compare “apples to apples” using this chart?

5. Student Satisfaction Data Excerpt ? Can you compare “apples to oranges” using this chart? Can you compare “apples to apples” using this chart?

6. Student Satisfaction Data Excerpt

7. Error 2 Correlation & Causation

8. Variables An aspect of someone or something that is free to vary – that is, different values are possible

9. Correlation How 2 variables change (vary) in relationship

10. CORRELATION

11. Correlations of ±1.00

12. An Interesting Correlation Sources: FBI Crime Statistics (http://www.fbi.gov/ucr/cius_04/documents/CIUS_2004_Section2.pdf) and USDA Dairy Statistics (http://usda.mannlib.cornell.edu/usda/nass/DairProd//2000s/2005/DairProd-02-04-2005.pdf)

13. Interesting Causation…? Landers, J.B. (n.d.). On CAUSEweb.org. Retrieved from http://www.causeweb.org/

14. Causation Causation has at least 3 requirements Correlation Temporal precedence Control (elimination) of other possible causes

15. Error 3 Two kinds of significance

16. Statistical Significance Null hypothesis significance testing ? H0

18. Result: confusion

19. Researchers report “significant finding”

20. Readers may think it’s substantial when it’s only reliable or fairly certain