Exploring the REsearch on Global Regression Expectations in StatisticS (REGRESS) quiz

1. Exploring the REsearch on Global Regression Expectations in StatisticS (REGRESS) quiz

2. The REGRESS Quiz • The REsearch on Global Regression Expectations in StatisticS (REGRESS) quiz • Intended as an outcome measure for courses focusing on regression • Competency-based constructs based on manuscript requirements • CONSORT • TREND • STROBE

3. CONSORT Guidelines for Randomized Controlled Trials

4. CONSORT Guidelines for Randomized Controlled Trials

5. CONSORT Guidelines for Randomized Controlled Trials

6. (Intended) Constructsin 26 Questions • What was found? • Interpretation & using the regression equation • Modeling & statistical significance • Effect modification

7. (Intended) Constructsin 26 Questions • What was found? • Interpretation & using the regression equation • Modeling & statistical significance • Effect modification • Assessing problems • Assessing assumptions • Confounding • Colinearity

8. Process • The REGRESS quiz is currently being validated • Undergraduates taking a course on regression • Graduate students taking a course on regression • Researchers who regularly use regression • Statisticians

9. Interpretation & Using the Regression Equation

12. 10 10 ∆Y ∆X 10 10 = = 1

14. When X=0, Y is about -20 10 10 10 10

15. In light of the obesity epidemic in the United States, the investigators also hoped to assess how body mass index (BMI) was associated with age among their patients.  Their regression model is shown on the plot below.  Which of the following statements is the best prediction that can be drawn from their results?

16. 9) Two studies were both designed to assess the relationship between the minutes spent washing hands and number of bacteria isolated following handwashing. The first set of researchers had no funding and obtained data on 25 people. The second set of researchers obtained funding to assess 250 people. Which of the following differences are likely to be observed between these two studies? (Choose all that apply) • larger p-value in the larger study • narrower confidence interval in the larger study • bigger coefficient of determination (R-squared) in the larger study • steeper slope in the larger study

17. 9) Two studies were both designed to assess the relationship between the minutes spent washing hands and number of bacteria isolated following handwashing. The first set of researchers had no funding and obtained data on 25 people. The second set of researchers obtained funding to assess 250 people. Which of the following differences are likely to be observed between these two studies? (Choose all that apply) • larger p-value in the larger study • narrower confidence interval in the larger study • bigger coefficient of determination (R-squared) in the larger study • steeper slope in the larger study

22. $690 - $430 = $260

29. Association is not causation!

33. Which regression model could have produced this graph? • Age is continuous • Marital status (married, single, or widowed), Ethnicity (Caucasian, African American, Hispanic, or Asian), and Gender (male or female) are all categorical

34. Which regression model could have produced this graph? • Age is continuous • Marital status (married, single, or widowed), Ethnicity (Caucasian, African American, Hispanic, or Asian), and Gender (male or female) are all categorical Two dummy variables = 3 lines

35. Which regression formula could have produced this graph, in which the green area represents the estimated value of Y?  Hint:  the graph is like two pieces of paper placed in a stack.

36. Which regression formula could have produced this graph, in which the green area represents the estimated value of Y?  Hint:  the graph is like two pieces of paper placed in a stack.

37. Which regression model could have produced this graph? • Age and Height are continuous • Gender (male or female) is binary

38. Which regression model could have produced this graph? • Age and Height are continuous • Gender (male or female) is binary

39. Which regression model could have produced this graph? • Age and Height are continuous • Gender (male or female) is binary Slopes: 1 and 0.5 2 and -2 2 – 4 = -2, so slope for one gender is negative

40. Which regression model could have produced this graph, in which the green area represents the estimated value of Y?  • Hint:  the green area is like a bent piece of paper. • Age and Height are continuous • Gender (male or female) is binary

41. Which regression model could have produced this graph, in which the green area represents the estimated value of Y?  • Hint:  the green area is like a bent piece of paper. • Age and Height are continuous • Gender (male or female) is binary Continuous x Continuous

42. Which regression model could have produced this graph, in which the green area represents the estimated value of Y?  • Hint:  the green area is like a bent piece of paper. • Age and Height are continuous • Gender (male or female) is binary Continuous x Continuous

43. (More) Effect Modification

46. Modeling & Statistical Significance

47. The investigators wondered whether body mass index (BMI) could be used to predict which patients would have an unusually high pulse rate.  The results of their regression analysis is below.  Based upon these data, is BMI statistically significantly associated with Pulse (the outcome Y) in this model?  Several conclusions are shown with different reasons below.  (Choose all that apply)

48. The investigators wondered whether body mass index (BMI) could be used to predict which patients would have an unusually high pulse rate.  The results of their regression analysis is below.  Based upon these data, is BMI statistically significantly associated with Pulse (the outcome Y) in this model?  Several conclusions are shown with different reasons below.  (Choose all that apply)