Class 5 and 6

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**1. **Class 5 and 6 Correlation
Correlation & Causation
Three scientific methods

**2. **The first team project (oral): Business idea proposal 15 minute presentation
5% of your total grade
Introduce your team’s business items
Three criteria
Innovativeness
Do-ability
Existence of market for the product/service

**3. **Agenda Team introduction
Correlation
Team exercise
Quiz

**4. **Variables An intervening (mediating) variable
Transmits the effects of a prior variable to a subsequent variable (A?B?C)
Helps us understanding why an how A affects C
A moderating (interaction) variable
Governs or limits the relationship between two other constructs
A causes B under some conditions

**5. **Diagram An intervening (mediating) variable

**6. **Graphical Depiction Click here for the excel File

**7. **Relationship btw two variables Covariance
Association between two variables based on multiple cases
Sensitive to units
Correlation
Linear association between two variables
Correlation coefficient: r
Unit free (-1 < r < 1)

**8. **Correlation Exercise In-Class activity
Quiz

**9. **Quiz Question
In one department of a design company, a manager named Sue observes that the level of absenteeism is pretty high. Sue knows that some people prefer to work at home; nevertheless, she is concerned that absenteeism from the office will hinder the performance of the designers. So, she decides to do a correlational study looking at absenteeism (the number of absences in one month) and performance (the number of designs accepted).

**10. **Quiz (2)

**11. **Quiz (3) Mean
Variance
Standard deviation
Covariance
Correlation

**12. **Quiz (4) Findings:
Absenteeism and performance has negative association
Conclusion (causal relationship)
Does absenteeism lead to low performance?
Does low performance lead to absenteeism?
Is there another possible explanation?

**13. **Quiz (5)

**14. **Quiz (6)

**15. **Correlational Study Correlation coefficient measures only the strength of association between two variables
It does not tell us about causality
The length of a women’s skirts and stock market price
Cannot rule out other possible explanation
High association between polio and Coke

**16. **Correlational Study (Cont.)

**17. **Correlational Study (Cont.)

**18. **Correlational Study (Cont.) No controlled manipulation
Manipulating independent variable at our discretion, holding other possible causes of dependent variable constant
Time
Longitudinal study
Observation of changes in X in time 1 correlates changes in time 2

**19. **Correlational Study (Cont.)

**20. **Correlational Study (Cont.)

**21. **Scientific vs. Non-scientific

**22. **Scientific Methods The objective
Accurate depiction of (causal) relationship
Causal relationship requires:
Correlation
Time sequence
Eliminate other possible causes

**23. **Scientific Methods (Cont.) Types
Naturalistic observation
Field survey research
Cross-sectional, correlational
Longitudinal
Experiments
Field
Laboratory

**24. **Naturalistic Observation

**25. **Field Survey Research

**26. **Why (Field or Lab) Experiment? Why experiment?
To determine what causes what
How do we see the causal relationship?
Observing whether changing X will produce a change in Y
How do we know that changes occurred?
By comparing two different groups

**27. **Debriefing In Class Experiment What are we interested in?
The effects of leader presence in a group activity in individual learning
Specific hypothesis in the next slide
What causes the variation of the amount?
Groups with leaders and without leaders
Causal relationship
The presence or absence of leader in the group during the correlation exercise will cause the difference in individual learning of the concept of correlation

**28. **Research Hypotheses Hypothesis
H1: Leader present group will perform better than leader absent group
H2: Prior statistical knowledge will lead to better performance
H3: The influence of prior statistical knowledge on performance will be stronger for leader present group than for leader absent group

**29. **Three Major Criteria for Good Experiments Random assignment
Manipulation
Control

**30. **Random Assignment What is it?
To assign participants into two different conditions
Without it one really does not have an experiment (Campbell & Stanley, 1963)
Does RA guarantee that the two groups are alike before manipulation
No
Then why?
Any differences due to the two groups will be due to the random process, which is unrelated with exp

**31. **Manipulation Manipulating independent variable
Presence of leader
Two groups
Experimental group (Manipulation)
Control group (No Manipulation)
How are we sure that there was manipulation?
Manipulation check

**32. **Control Holding an extraneous variable
An extraneous variable
A variable other than an independent variable that may influence the results of an experiment
What can be the example of extraneous variables in our experiment?

**33. **Pretest-posttest Control Group Design

**34. **Posttest-only Control Group Design

**35. **Experiment Result All the hypotheses were not supported… However......

**36. **Statistical Significance (old data)

**37. **In Class Exercise As a group, discuss the following:
What can you improve our class experiment given the three criteria of good experiment?
In your opinion, what kind of biases existed from your side or my side (experimenter) during the experiment?

**38. **Reliability and Validity Reliability
Consistency of measurement
Example:
Test-retest reliability
Split-half reliability
Coefficient alpha
Validity
The degree to which a research study is actually measuring what it claims to be measuring
Generalizability
The degree to which a research findings can apply to a different people, time, and settings