2. Introduction to Statistics for the Social Sciences SBS200, COMM200, GEOG200, PA200, POL200, or SOC200 Lecture Section 001, Fall 2015 Room 150 Harvill Building 10:00 - 10:50 Mondays, Wednesdays & Fridays.

3. Everyone will want to be enrolled in one of the lab sessions Lab continue this week, Project 1

4. Project 1 - Likert Scale - Correlations - Comparing two means (bar graph)

5. Homework Assignment No new homework assignments (Time to get caught up if you’ve fallen behind )

6. More information on registering clickers coming soon

7. Schedule of readings Before next exam (September 25 th ) Please read chapters 1 - 5 in OpenStax textbook Please read Appendix D, E & F online On syllabus this is referred to as online readings 1, 2 & 3 Please read Chapters 1, 5, 6 and 13 in Plous Chapter 1: Selective Perception Chapter 5: Plasticity Chapter 6: Effects of Question Wording and Framing Chapter 13: Anchoring and Adjustment

8. Time series versus cross-sectional comparisons: Trends over time versus a snapshot comparison Trends over time versus a snapshot comparison Time series design: Each observation represents a measurement at some point in time. Repeated measurements allow us to see trends. Cross-sectional design: Each observation represents a measurement at some point in time. Comparing across groups allows us to see differences. Please note: Any one piece of data can often (not always) be used in either a time series comparison or a cross-sectional comparison. It depends how you set up your question. Traffic accidents Does Tucson or Albuquerque have more traffic accidents (they have similar population sizes)? Does Tucson have more traffic accidents as the year ends and winter approaches?

9. Time series versus cross-sectional comparisons: Trends over time versus a snapshot comparison Trends over time versus a snapshot comparison Time series design: Each observation represents a measurement at some point in time. Repeated measurements allow us to see trends. Cross-sectional design: Each observation represents a measurement at some point in time. Comparing across groups allows us to see differences. Unemployment rate Is there an increase in workers calling in sick as the summer months approach? Do more young workers call in sick than older workers? Grade point average (GPA) Does GPA tend to go up or down as students move from freshman to sophomores to juniors to seniors? Does GPA tend to go up or down when you compare Mr. Chen’s class with Mr. Frank’s Freshman English classes?

10. Raw scores, z scores & probabilities Please note spatially where 1 standard deviation falls on the curve

11. Raw scores, z scores & probabilities 68% 95%99.7% Please note spatially where 1 standard deviation falls on the curve

12. Standard deviation: The average amount by which observations deviate on either side of their mean Based on difference from the mean Mean Diallo is 0” Mike is -4” Hunter is -2 Shea is 4 David 0” Preston is 2” Deviation scores Mike Shea Preston Diallo Generally, (on average) how far away is each score from the mean? Remember, it’s relative to the mean Please memorize these “Sum of Squares” “n-1” is “Degrees of Freedom” “n-1” is “Degrees of Freedom” Remember, We are thinking in terms of “deviations”

13. Standard deviation: The average amount by which observations deviate on either side of their mean Based on difference from the mean Mean Diallo is 0” Mike is -4” Hunter is -2 Shea is 4 David 0” Preston is 2” Deviation scores Mike Shea Preston Diallo Generally, (on average) how far away is each score from the mean? Remember, it’s relative to the mean Please memorize these “Sum of Squares” “n-1” is “Degrees of Freedom” “n-1” is “Degrees of Freedom” Remember, We are thinking in terms of “deviations”

14. Summary of 7 facts to memorize

15. 1. What is a “deviation score” 2. Preston has a deviation score of 2: What does that tell us about Preston? Is he taller or shorter than the mean? And by how much? Are most people in the group taller or shorter than Preston 3.Mike has a deviation score of -4: What does that tell us about Mike? Is he taller or shorter than the mean? And by how much? Are most people in the group taller or shorter than Mike 4.Diallo has a deviation score of 0: What does that tell us about Diallo? Is he taller or shorter than the mean? And by how much? Are most people in the group taller or shorter than Diallo? 5.Please write the formula for the standard deviation of a population 6.Please draw 3 curves showing 1, 2 & 3 standard deviations from mean Writing Assignment – Pop Quiz

16. 7. What does this symbol refer to? 8. What does this symbol refer to? 11. What does this symbol refer to? 9. What does this symbol refer to? 10. What does this symbol refer to? What is it called? What does it mean? Is it referring to a sample or population? What is it called? What does it mean? Is it referring to a sample or population? What is it called? What does it mean? Is it referring to a sample or population? What is it called? What does it mean? Is it referring to a sample or population?

17. Writing Assignment – Pop Quiz 12. What does this refer to? 13. What does this refer to? 14. What do these two refer to? 15. What does this refer to? What are they called? How are they different What is it called? Use it for sample data or population? What are they called? What do they refer to? How are they different What are they called? How are they different

18. Writing Assignment – Pop Quiz 16. What does this refer to? What are they called? What do they refer to? How are they different 17. What does this refer to? What are they called? What do they refer to? How are they different

19. 1. What is a “deviation score” 2. Preston has a deviation score of 2: What does that tell us about Preston? Is he taller or shorter than the mean? And by how much? Are most people in the group taller or shorter than Preston 3.Mike has a deviation score of -4: What does that tell us about Mike? Is he taller or shorter than the mean? And by how much? Are most people in the group taller or shorter than Mike 4.Diallo has a deviation score of 0: What does that tell us about Diallo? Is he taller or shorter than the mean? And by how much? Are most people in the group taller or shorter than Diallo? 5.Please write the formula for the standard deviation of a population 6.Please draw 3 curves showing 1, 2 & 3 standard deviations from mean How far away is each score from the mean? Preston is 2” taller than the mean (taller than most) Mike is 4” shorter than the mean (shorter than most) Diallo is exactly same height as mean (half taller half shorter) Writing Assignment – Pop Quiz

20. 7. What does this symbol refer to? 8. What does this symbol refer to? 11. What does this symbol refer to? 9. What does this symbol refer to? 10. What does this symbol refer to? What is it called? What does it mean? Is it referring to a sample or population? What is it called? What does it mean? Is it referring to a sample or population? What is it called? What does it mean? Is it referring to a sample or population? What is it called? What does it mean? Is it referring to a sample or population? The standard deviation (population) The mean (population) The mean (sample) The standard deviation (sample) Each individual score sigma population mu x-bar population sample s

21. 12. What does this refer to? 13. What does this refer to? 14. What do these two refer to? 15. What does this refer to? What are they called? How are they different What is it called? Use it for sample data or population? What are they called? What do they refer to? How are they different What are they called? How are they different Variance population sample Sigma squared S squared Deviation scores population sample Sum of squares population sample Degrees of freedom Writing Assignment – Pop Quiz

22. 16. What does this refer to? What are they called? What do they refer to? How are they different 17. What does this refer to? What are they called? What do they refer to? How are they different Variance population sample Standard Deviation population sample