ch03

The Importance of Studying Relationships
Scientists value research that investigates relationships more highly than purely descriptive research
What is a Variable?
Group presentations
Educational systems questionaire Handout 2 A,B,C
BREAK
Variables and Hypotheses
Chapter Three
Variables and Hypotheses
Chapter Three
– A manipulated variable is a changed condition the researcher creates during a study, also known as an experimental or treatment variable – A selected variable is an independent variable that already exists
Moderator Variable (interaction)
– Special type of independent variable – Selected to determine if it affects (modifies) the basic relationship between the primary independent variable and the dependent variable (Figure 3.2)
Quantitative vs. Categorical Variables
Variables are classified as either quantitative or categorical A quantitative variable is conceptualized and analyzed in distinct categories, with no continuum implied (e.g., height).
Chapter 2
Summary group 2 presentation
Chapter 2
What Is a Research Problem? - A research problem is the focus of a research investigation. - Problems involve areas of concern to researchers, conditions they want to improve, difficulties they want to eliminate, and questions for which they seek answers. Research Questions - Many research problems are stated as questions. - The essential characteristic of a researchable question is that there is some sort of data that can be collected in an attempt to answer the question. Characteristics of Good Research Questions - Research questions should be feasible—capable of being investigated with available feasible— resources. - Research questions should be clearly written—that is, unambiguous. written— - Research questions should be significant—that is, worthy of investigation. significant— - Research questions often investigate relationships. The term “relationship” as used in research refers to a connection or association between two or more characteristics or qualities. Defining Terms in Research Three commonly used ways to clarify ambiguous or unclear terms in a research question involve: the use of constitutive (dictionary-type) definitions, definition by (dictionaryexample, and operational definitions. A constitutive definition uses additional terms to clarify meaning. An operational definition describes how examples of a term are to be measured or identified.
The Relationship between Independent and Dependent Variables
Other Types of Variables
Outcome Variable
– A dependent variable that is quantitative – Most studies demonstrating this would have a categorical independent variable – The investigator is interested in the effects that might lead to differences in methods = outcomes
– Presumed or possible cause
The dependent variable is what is being influenced or affected by the independent variable
– Presumed results
Independent variables may be either manipulated or selected
Data entry Key
1. B 2. D 3. C 4. A 5. A 6. C 7. B 8. C 9. C 10. B 11. D 12. A 13. D 14. B 15. A 16. B 17. D 18. B 19. C 20. A 21. D 22. A 23. A 24. C 25. B 26. C 27. A 28. A 29. A 30. B 31. A 32. B 33. B 34. A 35. A 36. B 37. B
Other Types of Variables (cont.)
Extraneous Variable
– Independent variables that have not been controlled – Considered a basic problem in research – The task is to control these variables by reducing or eliminating their effects – A method to control extraneous variables is to hold them constant – Figure 3.3 illustrates the importance of identifying extraneous variables
A variable is a variation within a class of objects (e.g., eye color). A constant is a characteristic with no variations within a class of objects (e.g., grade level of ninth graders). Researchers choose certain variables to study since they are suspected to be related to a possible relationship to be discovered.
Today
Problems?? Recapitalisation chapter 2 SPSS (Testdata, key) Group presentations (Interview, exercise) Class discussion Lecture Class exercise Questions Homework Next week
Syntax
Editor to type codes Paste codes from menu Syntax tells the computer what to do Reading data Recoding, calculating Analysing output
Advantages syntax
Format variables recode
Studentnumber numeric 8 v1 to v37 string length 1 Values of string variables between quotes “ “ You can not calculate with string variables! So, we need new numerical variables We recode v1 to v37 into new numerical variables qv1 to qv37 by use of key into 1 0 variable (dichotome) Numeric(qv1 to qv37). Recode v1(“A”=0)(“B”=1)(“C”=0)(“D”=0)into qv1. syntax