Introduction to Statistics in Psychological Research

descriptive research

allows us to describe a behaviour or phenomena

relational research

allows us to predict a behaviour or phenomena based on its relationship with another behaviour or phenomena.

experimental research

• allows us to determine the cause of a behaviour or phenomena

• manipulation of one or more variables in order to determine the effect of another variable

• other variables which may affect the outcome are kept constant

• determines whether any differences arise as a direct result of the manipulation

why can’t we infer causality from correlations?

we can’t rule out the possibility that relationships are coincidental or the influence of other factors

methodological triangulation

combining different approaches for deeper insights

what is a theory

a theory is a set of connected ideas that help us understand and predict behaviour. they are the base of forming hypotheses.

Hypothesis

A clear, testable statement predicting the relationship between variables

what are the features of a good hypothesis?

• falsifiable- able to be disproven

• testable- can collect data to evaluate it

• precisely stated- clear, specific language

• rational- should make sense in the context of existing knowledge or theory

• parsimonious- as simple as possible

what is a construct?

theoretical concepts that provide scaffolding for the measurement tools that we use

what is a variable?

• any characteristic or condition that can vary

• measurable form of a construct

Variables must be operationalised, what does this mean?

clearly defined in terms of how they will be measured

• quantifiable

• testable

what is the hypothetic-deductive method?

1. observation

2. intuition

3. theory development

4. derive a hypothesis

5. specific, testable predictions

6. hypothesis testing

7. reflecting and revising

what is an extraneous variable?

Any variable other than IV, that could influence the DV

what is a confounding variable?

A type of extraneous variable that directly affects the DV

How can you reduce the impact of extraneous variables?

Randomisation and counterbalancing

what is a population?

The entire group you are interested in

What is a sample?

Subset of a population

what is a random sample?

it is when every member of the population has an equal chance of being chosen