2. Introduction to Statistics for the Social Sciences SBS200, COMM200, GEOG200, PA200, POL200, or SOC200 Lecture Section 001, Spring 2015 Room 150 Harvill Building 8:00 - 8:50 Mondays, Wednesdays & Fridays. http://courses.eller.arizona.edu/mgmt/delaney/d15s_database_weekone_screenshot.xlsx

3. Schedule of readings Before next exam (February 13 th ) Please read chapters 1 - 4 in Ha & Ha 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

4. Exam 1 – This Friday – February 13 th Study Guide is online Bring 2 calculators (remember only simple calculators, we can’t use calculators with programming functions) Bring 2 pencils (with good erasers) Bring ID

6. Everyone will want to be enrolled in one of the lab sessions Labs continue this week with Project 1 and Prep for Exam 1

7. By the end of lecture today 2/11/15 Use this as your study guide Measures of variability Memorizing the four definitional formulae The “empirical rule” Review for Exam 1

8. No Homework due Friday, Feb 13 th Just study for Exam 1

9. Random sampling vs Random assignment Random sampling of participants into experiment: Each person in the population has an equal chance of being selected to be in the sample Random assignment of participants into groups: Any subject had an equal chance of getting assigned to either condition (related to quasi versus true experiment) Review

10. From the lab review Mariska works at a cattle ranch, and wants cattle to gain as much weight as possible. Mariska wants to know if the new feed makes a difference in how much weight the cattle gain. She gathers the first 100 cows that she finds in the meadow, and then randomly assigns those 100 cows into two groups (50 each group) One group gets the new feed for 6 months, while the other group of cattle gets the old feed. She is not looking for any trends over time, but is just looking for a difference between the two types of cow chow (feed). Independent Variable? Dependent Variable? IV: Nominal Ordinal Interval or Ratio? DV: Nominal Ordinal Interval or Ratio? IV: Continuous or discrete? DV: Continuous or discrete? Type of Cow Chow Weight IV: Nominal DV: Ratio IV: Discrete DV: Continuous Random Assignment? Random Assignment (True Expt) Random Sampling? No, only convenience sampling Between or within? Between Participant Design Cross Sectional or Time Series Cross Sectional

12. Scores on an exam Score Frequency 95 - 992 90 - 94 3 85 - 89 5 80 – 845 75 - 79 4 70 - 74 3 65 - 69 1 60 - 64 3 55 - 59 1 50 - 54 1 Step 6: Complete the Frequency Table Scores on an exam 82 58 64 80 75 72 87 73 88 94 84 78 93 69 70 60 53 84 76 87 84 61 89 95 87 91 75 99 Cumulative Frequency 28 26 23 18 13 9 6 5 2 1 Relative Frequency.0715.1071.1786.1429.1071.0357.1071.0357 Relative Cumulative Frequency 1.0000.9285.8214.6428.4642.3213.2142.1785.0714.0357 6 bins Interval of 8 Just adding up the frequency data from the smallest to largest numbers Just dividing each frequency by total number to get a ratio (like a percent) Please note: 1 /28 =.0357 3/ 28 =.1071 4/28 =.1429 Just adding up the relative frequency data from the smallest to largest numbers Please note: Also just dividing cumulative frequency by total number 1/28 =.0357 2/28 =.0714 5/28 =.1786 Review

13. Summary of 7 facts to memorize

14. 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”

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

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

17. Raw scores, z scores & probabilities Mean = 50 S = 10 (Note S = standard deviation) If we go up one standard deviation z score = +1.0 and raw score = 60 If we go down one standard deviation z score = -1.0 and raw score = 40 1 sd above and below mean 68% z = -1 z = +1

18. Mean = 50 S = 10 (Note S = standard deviation) If we go up two standard deviations z score = +2.0 and raw score = 70 If we go down two standard deviations z score = -2.0 and raw score = 30 2 sd above and below mean 95% Raw scores, z scores & probabilities z = -2 z = +2

19. Mean = 50 S = 10 (Note S = standard deviation) If we go up three standard deviations z score = +3.0 and raw score = 80 If we go down three standard deviations z score = -3.0 and raw score = 20 3 sd above and below mean 99.7% Raw scores, z scores & probabilities z = -3 z = +3

20. Review of Homework Worksheet

21. -2 1 3 0 3 – 5 = -2 3 -3 1 6 – 5 = +1 50 -2 2 = 4 1 2 = 1 4 1 9 1 0 9 9 1 1 1 36 10 - 1 = 2 2 5 4.5 28 6 4.625 0 Review of Homework Worksheet

22. 2 3 0 5 – 6 = -1 0 3 1 -5 8 – 6 = +2 60 -1 2 = 1 2 2 = 4 1411914119 0 1 9 1 25 52 10 - 1 = 2.4 2.4 65.5 1 9 8 5 Review of Homework Worksheet

23. Must be complete and must be stapled

24. 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

25. 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