Ways to Acquire Knowledge

• Intuition: opinion, belief, gut feeling (“common sense”)
• Authority: information from experts or trusted sources
• Rational induction: combining known facts to infer new knowledge
• Empiricism: direct observation of the world
• Scientific method: systematic collection and evaluation of data
• All are valid for generating hypotheses
• Only empiricism via the scientific method is valid for testing hypotheses

Empirical Research in Psychology

• Empirical research = collecting new data
• Most psychology research is quantitative
• Some research is qualitative
• Some studies use mixed methods (quantitative + qualitative)

Quantitative vs Qualitative Methods

Method	Data type	Examples
Quantitative	Numeric	experiments, surveys
Qualitative	Descriptive	interviews, focus groups, open-ended responses
Mixed methods	Both	combines quantitative and qualitative approaches

Research Design Types

• Quantitative
  • Experimental (between-subjects, within-subjects)
  • Non-experimental (quasi-experimental, correlational)
• Qualitative
  • Interviews
  • Focus groups
  • Open-ended survey questions

Steps in Conducting Empirical Research

1. Observation and literature review
2. Form research question and hypotheses
3. Design the study
   • select study design
   • identify population, sample, sampling method
   • operationalise constructs
   • obtain ethics approval
4. Conduct the study and collect data
5. Analyse the data
6. Draw conclusions and disseminate findings

Aim, Research Question, Research Hypothesis

Term	Definition
Aim	Broad purpose of the study
Research question	What the study aims to answer
Research hypothesis	Specific, testable prediction

• Research hypotheses are central to scientific research
• Good hypotheses:
  • specify relationships between variables
  • are often directional
  • are theory-based
  • are testable and falsifiable

Study Design Basics

• Design choice depends on:
  • research question and hypotheses
  • feasibility and practical constraints
  • ethical guidelines
• Research questions are about populations
• Data are collected from samples
• Conclusions are generalised back to populations

Operationalisation

• Turning psychological constructs into measurable variables
• Aim to maximise reliability and validity

Ethics

• All research must be ethically approved
• Ethics committees weigh risk versus benefit
• Approval required before data collection

Data Analysis

• Descriptive statistics: summarise the sample
• Inferential statistics: generalise from sample to population
• Sample summaries = statistics
• Population summaries = parameters

Research vs Statistical Hypotheses

Type	Description
Research hypothesis	Conceptual prediction derived from theory
Null hypothesis (H₀)	No effect or no difference
Alternative hypothesis (H₁)	An effect or difference exists

Directional vs Non-Directional Hypotheses

• Research hypotheses are usually directional
• Statistical alternative hypotheses are often non-directional

Summarising Data

• Always begin by summarising each variable
• Summary method depends on variable type

Variable types

• Categorical: nominal, ordinal
• Numerical: interval, ratio

Measures of Centre

Measure	Notes
Mean	affected by outliers
Median	robust to outliers
Mode	most common value

Measures of Spread

Measure	Notes
Range	highly affected by outliers
Interquartile range (IQR)	robust to outliers
Variance	affected by outliers
Standard deviation (SD)	affected by outliers

Shape of Distributions

• Symmetric: mean = median = mode
• Skewed:
  • left-skewed: tail on the left
  • right-skewed: tail on the right
• Bimodal or multimodal distributions possible
• Kurtosis describes how peaked or flat a distribution is

STATA Commands: Summarising Data

• One categorical variable (frequency table)
  tabulate variable
• Multiple categorical variables
  tab1 var1 var2
• Numeric summaries (centre, spread)
  summarize variable
• Detailed numeric summaries (incl. IQR)
  summarize variable, detail
• Custom summary tables
  tabstat var1 var2, stats(mean sd median min max iqr)
• Help menu for options
  help tabstat

Sharing Research Findings

• Research findings can be disseminated through:
  • journal articles
  • conferences
  • books
  • communication with others
• Psychology research reports follow APA style

Structure of a Psychology Research Report

Section	Purpose
Abstract	Summary of the entire study
Introduction	Context, literature, gap, hypotheses
Method	How the study was conducted
Results	Findings with minimal interpretation
Discussion	Interpretation, limitations, implications
Reference list	Sources cited