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

Everyone will want to be enrolled in one of the lab sessions Labs start This week with Project 1

Homework Assignment 1 due Monday, August 31 st Go to D2L - Click on “Content” Click on “Interactive Online Homework Assignments” Complete Assignment 2: HW2-Part1-Quasi-experimental Designs versus True Experiments HW2-Part2-Between versus Within Participant Design Due: Wednesday, September 2nd

More information on registering clickers coming soon

Schedule of readings Before next exam (September 25 th ) Please read chapters 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

By the end of lecture today 8/31/15 Use this as your study guide Project 1 Composite Score (Likert Scale) Correlations Scatterplots Comparing two means Bar graphs

Remember bring your writing assignment forms notebook and clickers to each lecture

Project 1 Likert Scale (summated scale) Correlation (scatterplots) Comparing two means (bar graph)

Likert Scale is always a “summated scale” with multiple items. All items are measuring the same construct. The score reflects the sum of responses on a series of items. - miniquiz (like Cosmo - ask several questions then sum responses) 1. Lower taxes and a smaller government will improve the standard of living for all. government will improve the standard of living for all. agree disagree - For example, several questions on political views (coded so that larger numbers mean “more liberal”) 2. Marriage should be between one man and one woman agree disagree 3. Evolution of species has no place in public education agree disagree

Anchored rating scales: a written description somewhere on the scale Agree Disagree Fully anchored rating scales: a written description for each point on the scale Strongly Agree Strongly Disagree AgreeDisagree Neutral I prefer rap music to classical music Likert Scale is always a “summated scale” with multiple items. All items are measuring the same construct. The score reflects the sum of responses on a series of items.

Likert Scale is always a “summated scale” with multiple items. All items are measuring the same construct. The score reflects the sum of responses on a series of items.

Project 1 Likert Scale (summated scale) Correlation (scatterplots) Comparing two means (bar graph)

Scatterplot displays relationships between two continuous variables Correlation: Measure of how two variables co-occur and also can be used for prediction Range between -1 and +1 Range between -1 and +1 The closer to zero the weaker the relationship The closer to zero the weaker the relationship and the worse the prediction Positive or negative Positive or negative

Height of Mothers by Height of Daughters Positive Correlation Height of Daughters Height of Mothers Positive correlation: as values on one variable go up, so do values for the other variable Negative correlation: as values on one variable go up, the values for the other variable go down

Brushing teeth by number cavities Negative Correlation Number Cavities Brushing Teeth Positive correlation: as values on one variable go up, so do values for the other variable Negative correlation: as values on one variable go up, the values for the other variable go down

Perfect correlation = or One variable perfectly predicts the other Negative correlation Positive correlation Height in inches and height in feet Speed (mph) and time to finish race

Correlation Range between -1 and +1 Range between -1 and perfect relationship = perfect predictor perfect relationship = perfect predictor 0 no relationship = very poor predictor strong relationship = good predictor strong relationship = good predictor strong relationship = good predictor weak relationship = poor predictor weak relationship = poor predictor weak relationship = poor predictor

Correlation

Correlation - How do numerical values change? Let’s estimate the correlation coefficient for each of the following r = +1.0r = -1.0 r = +.80 r = -.50r =

Project 1 Likert Scale (summated scale) Correlation (scatterplots) Comparing two means (bar graph)

One positive correlation One negative correlation Comparing Two means “Serious Gamer” Score Time Studying Age “Serious Gamer” Score Gender

Project 1 Likert Scale (summated scale) Correlation (scatterplots) Comparing two means (bar graph) Questions?