Advanced Research Methods And Statistics For Psychology (201900076)
All documents for this subject (9)
Seller
Follow
annaverstoeppie
Content preview
ARMS College 1 – Multiple Linear Regression
- Birth order effects: scientific research has demonstrated that firstborns
have higher IQ than later born (Galton, 1874). --> You have to critically
review the way the studies were performed and critically consider
alternative explanations for the statistical association. (association is not
causation).
- Adding variables
o Simple linear regression: involves 1 outcome (y) and 1 predictor
(x). (dependent variables and independent variable).
o Multiple linear regression: involves 1 outcome and multiple
predictors.
To what extend does the model explain variation in the data –
the amount of variance (R²) i.e. the sizes of the residuals.
Large R²: dots/scores are close to the line.
Smaller R²: dots/score are not very close to the line.
The slope of the regression line (B1): The predicted outcome
increases with the slope of the line. If the slope is steep, the
B1 value is large. If it is horizontal, B1 is close to 0.
- Things you need to know about Multiple linear regression (MLR)
o The model
o Types of variables in MLR
o MLR and Hierarchical MLR
Hypothesis
Output
Model fit: R², adjusted R² and R²-change
Regression coefficients: B and Beta (=standardized B)
o Exploratory MLR (stepwise) versus confirmatory MLR (forced entry)
o Model assumptions important to MLR (grasple)
- The model
o
- Types of variables
o Nominal & Ordinal are categorical or qualitative.
o Interval & Ratio are continuous or quantitative or numerical.
o MLR requires continuous outcome and continuous
predictors.
o But categorical predictors can be included as dummy
variables.
Dummy coding: dummy has only values 0 and 1.
Categorical predictors with more than 2 levels, by example
colour: multiple dummy variables.
,
- MLR and hierarchical MLR
ARMS College 2 – Moderation and Mediation
- Linear additive model: two predictors, for each of them we assume a linear relation with the
outcome variable. These effects add up.
- This week: moderation and mediation.
- Moderation: the effect of predictor X1 on outcome Y is different for different levels of
second predictor X2. Gender affects the relationship between X1 and Y.
Gender affects the relationship between X1 and Y.
Gender and X1 together have an additional effect not
captured in the two main effects.
o
- How many regression models you will see: number of outcomes * number of measures.
- Inflated type 1 error: risk of making a mistake is usually at a=0.05. They inflate when there is
multiple testing.
- Testing for interactions:
- Mediation: the effect of the independent variable on a dependent variable is explained by a
third intermediate variable.
There can be complete or partial mediation.
Notation:
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller annaverstoeppie. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.29. You're not tied to anything after your purchase.