1. Week 5 ETEC 668 Quantitative Research in Educational Technology
Dr. Seungoh Paek
February 12, 2014

2. Tonight’s Agenda Continuing SPSS Introduction to PSPP
Introduction to RStudio
Introduction to Probability
Group Discussion for Research Paper

3. Continuing Week 4

4. Using SPSS

5. Using SPSS

6. Sigma Freud & Descriptive Statistics
A Picture is Really Worth a Thousand Words

7. Histograms with Polygon
Hand Drawn Histogram

8. Cool Ways to Chart Data
Line Chart

9. Cool Ways to Chart Data
Pie Chart

10. Using the Computer to Illustrate Data
Creating Histogram Graphs

11. Using the Computer to Illustrate Data
Creating Bar Graphs

12. Using the Computer to Illustrate Data
Creating Line Graphs

13. Using the Computer to Illustrate Data
Creating Pie Graphs

14. A Taste of PSPP

15. Download PSPP - For Mac, click here. For Window, click here.

16. A TASTE of RSTudio

17. R
R is a free software environment for statistical computing and graphics.

18. RStudio
RStudio is a free and open source integrated development environment (IDE) for R, a programming language for statistical computing and graphics.

19. Probability, Samples, Bell Curve, z Scores, Hypotheses, Hypothesis Testing, & significance
Chapter 7 & Chapter 8

20. Probability

21. Why Probability?
Describe and predict what we don’t know from current data
Basis for the Degree of confidence a Hypothesis is “true”
statistical significance

22. Examples Flip a coin Role a Die Flip 2 coins 2 possible outcomes
Heads or Tails
50% chance each
Role a Die
6 possible outcomes
1 – 2 – 3 – 4 – 5 – 6
16.6% chance each
Flip 2 coins
How many possible outcomes?
What % chance for each?

23. Examples Flip 2 coins 4 possible outcomes 25% chance each 1 2 3 4
Coin A
Coin B 1 2 3 4
Flip 2 coins
4 possible outcomes
25% chance each

24. Sample v Population

25. Definitions Population Sample
The large group to which you would like to generalize your findings
Sample
The smaller, representative group of the population used for research.

26. Characteristics of a sample
Needs to be representative
Truly random = representative = unbiased
Sampling error –
how well the sample represents the population
Size matters –
larger sample = more representative

27. Mathematical Symbols Mean Standard Deviation Variance Number of Cases
Population = μ
Sample = X
Standard Deviation
Population = σ
Sample = SD
Variance
Population = σ2
Sample = SD2
Number of Cases
Population = N
Sample = n

28. The Normal Curve

29. The Normal curve

30. More Normal Curve

31. About Normal Curve
Almost all scores fall between -3 and +3 SD from mean
99.74%
Specific percentages between points on x-axis
2 or more normal curves can be compared

32. Normal Curve and Percents

33. z Scores

34. The z Score The number of standard deviations from the mean
Negative scores are below (left of) the mean
Positive scores are above (right of) the mean

35. = The z Score Standard Score Allows you to compare apples and oranges
The probability of a score occurring =

36. Hypotheses

37. What is a Hypothesis? An “educated guess”
Direct extension of the question
Translates problem or research question into a testable form
Two types
Null Hypothesis
Research Hypothesis

38. A Good Hypothesis Declarative statement
Expected relationship between variables
Reflection of theory/literature
Brief, to the point
Testable

39. Why a Null Hypothesis?
No amount of experimentation can ever prove me right; a single experiment can prove me wrong.
~ Albert Einstein

40. The Null Hypothesis Statement of no relationship Two things are equal
H0 : μA = μB
Refers to Population
Indirectly tested

41. The Research Hypothesis
Definite Statement
Relationship exists between variables
Two types
Nondirectional - H1 : XA ≠ XB
Directional - H1 : X1 > X2
Refers to sample
Directly tested

42. Hypothesis Testing

43. Hypothesis Testing All events have a probability associated with them
p = your guess of chance
p < .05
.05 or 5% in Education and Psychology
5% likelihood of results occurring by chance alone

44. Error types Type I Type II Reject H0 when you should not
Fail to reject H0 when you should

45. Error Table Investigator’s Decision H0 is True H0 is False Reject H0
The Real Situation
(Unknown to investigator)
Investigator’s Decision
H0 is True
H0 is False
Reject H0
Type I error
Correct decision
Do Not reject H0
Type II error

46. Significance

47. Statistical Based on probability Research was technically successful
H0 was rejected
P value
Education p < .05 = 5% chance
Medical p < .01 or .001 = 1% or .1% chance

48. Practical Does it mean anything to the population?
Is that new treatment worth the cost?
Are my students really doing that much better?

49. Questions?

50. Stating the Research Question
February 12, 2014

51. Where are we now? Identified a problem focus
Familiar with the literature
Next step – determine specific questions for your research study
Research questions provide the basis for planning research study – design, materials, data analysis

52. Can meaningful learning be enhanced by using a computer to personalize math word problems for each student?

53. Research Questions vs Research Hypotheses

54. Research Questions in Qualitative Research
Preferred when little is known about a phenomenon
Used when previous studies report conflicting results
Used to describe phenomena

55. Research Hypotheses for Quantitative Research
Educated guess or presumption based on literature
States the nature of the relationship between two or more variables
Predicts the research outcome
Research study designed to test the relationship described in the hypothesis .

56. Null Hypotheses
Implicit complementary statement to the research hypothesis
States no relationship/difference exists between variables
Statistical test performed on the null
Assumed to be true until support for the research hypothesis is demonstrated

57. Alternative Hypotheses
Directional hypothesis
Precise statement indicating the nature and direction of the relationship/difference between variables
Nondirectional hypothesis
States only that relationship/difference will occur

58. Assessing Hypotheses Simply stated? Single sentence?
At least two variables?
Variables clearly stated?
Is the relationship/difference precisely stated?
Testable?

59. Types of Variables Variable
Element that is identified in the hypothesis or research question
Property or characteristic of people or things that varies in quality or magnitude
Must be identified as independent or dependent

60. Independent Variables (IV)
Manipulation or variation of this variable is the cause of change in other variables
Technically, independent variable is the term reserved for experimental studies
Also called antecedent variable, experimental variable, treatment variable, causal variable, predictor variable

61. Dependent Variables (DV)
The variable of primary interest
Research question/hypothesis describes, explains, or predicts changes in it
The variable that is influenced or changed by the independent variable
In non-experimental research, also called criterion variable, outcome variable

62. Intervening or Mediating Variables
Intervening/Mediating variable
Presumed to explain or provide a link between independent and dependent variables
Relationship between the IV and DV can only be explained when the intervening variable is present
E.g. effect of study prep on test scores
Organization of study ideas into a framework (intervening/mediating)

63. Control Variables
Special type of IV that can potentially influence the DV
Use statistical procedures (e.g. analysis covariance) to control for these variables
May be demographic or personal variables that need to be “controlled” so that true influence of IV on DV can be determined

64. Confounding Variables
Confuses or obscures the effect of independent on dependent
Makes it difficult to isolate the effects of the independent variable
Typically cannot be directly measured or observed
Researchers comment on the influence after study is completed

65. Relationship Between Independent and Dependent Variables
Cannot specify independent variables without specifying dependent variables
Number of independent and dependent variables depends on the nature and complexity of the study
The number and type of variables dictates which statistical test will be used

66. Model for Writing Descriptive Questions & Hypotheses
Identify IV, DV & any intervening/moderating variables
Specify descriptive questions for each IV, DV & intervening variable
Write inferential questions that relate variables or compare groups

67. Scenario
A researcher wants to study the relationship of critical thinking skills to student achievement in science classes for 8th-graders in a large metropolitan school district. The researcher controls for the effects of prior grades in science classes and parents’ educational attainment.

68. Step 1: Identify variables
What is the IV?

69. Step 1: Identify variables
What is the IV?
Critical thinking skills (measured on an instrument)

70. Step 1: Identify variables
What is the DV?

71. Step 1: Identify variables
What is the DV?
Student achievement (measured by grades)

72. Step 1: Identify variables
What are the control variables?

73. Step 1: Identify variables
What are the control variables?
Prior grades in science class
Educational attainment of parents

74. Descriptive Questions
How do the students rate on critical thinking skills?
What are the students’ achievement grades in science classes?
What are the students’ prior grades in science classes?
What is the educational attainment of the parents of the 8th graders?

75. Inferential Questions
Does critical thinking ability relate to student achievement?
Does critical thinking ability relate to student achievement, controlling for the effects of prior grades in science and the educational attainment of the 8th-graders’ parents?

76. What to do Week 5 Do the required readings for Week 06.
Salkind, N. J. Chapter 16. Redicting Who’ll Win the Super Bowl: Using Linear Regression
Salkind, N. J. Chapter 20. The Ten (or More) Best Internet Sites for Statistics Stuff
Continue the group discussion on the final research paper, and post the 1) literature review outline and 2) research questions for your paper to the Forum in Laulima (Due by Tuesday, February 18th).