Summary of Core Concepts and Methods

Overview

This set of lectures covers core concepts in inferential statistics, brain anatomy and MRI methods, qualitative research methodologies, social psychology, and cultural/indigenous psychology, along with practice exam questions.

Core Concepts in Inferential Statistics

• Inferential statistics draw population conclusions from sample data using probability.
• Sampling distribution: possible values of a statistic across all samples of size n.
• Central Limit Theorem: sampling means are approximately normal if n is large, enabling use of z-scores.
• Standard Error (SE): estimated variability of the sample mean.
• Hypothesis testing steps: form hypothesis, collect sample, compare using probabilities and z-scores.
• One- vs two-tailed tests: predict direction or not; critical values differ.

Decision Errors in Hypothesis Testing

• Type I Error: rejecting true H₀; probability = α.
• Type II Error: failing to reject false H₀; probability = β; Power = 1-β.
• Reducing Type II Error: increase α, sample size, test power, or experimental quality.

t-Tests and Unknown SD

• When σ unknown and n small, use t-distribution with df = n-1.
• Single-sample t-test compares sample mean to hypothesized μ.
• Two-sample t-test compares two group means; use appropriate standard error.

Brain Anatomy and MRI

• Neurons: cell body, dendrites, axon, myelin; transmit signals in the brain.
• Grey matter: cell bodies/dendrites; processes info, decision-making.
• White matter: myelinated axons; connects regions, enables communication.
• MRI: uses magnetic fields to image brain tissue; structural MRI shows anatomy, dMRI shows axons, fMRI shows brain activity.

MRI Methods and Applications

• Structural MRI: <1mm resolution, visualizes structure, used clinically for tumors/injury.
• Diffusion MRI: lower resolution, measures water diffusion along axons, assesses white matter integrity.
• Functional MRI: measures blood oxygenation (BOLD), shows brain activation; 1-3s/image.
• Limitations: each method has restricted resolution, artifacts, and indirect measurements.

Qualitative Research Overview

• Focuses on subjective experience, meaning, and context.
• Data: interviews, focus groups, photos, media; analyzed via thematic, narrative, or grounded theory methods.
• Emphasizes reflexivity, ontology, epistemology.
• Sampling is purposeful, not random; questions are open-ended.

Mixed Methods and Research Design

• Mixed methods combine qualitative and quantitative data for fuller understanding.
• Driven by pragmatism; requires careful integration, sequencing, and clear research purpose.
• Research can be basic (theory-building) or applied (real-world solutions).

Social and Cultural Psychology

• Social norms: descriptive (what is done) and injunctive (what should be done).
• Culture: shared knowledge, behaviors, meanings; influences psychology.
• Etic (outsider) vs emic (insider) research perspectives.
• Indigenous psychology uses local knowledge systems, bottom-up approaches, and addresses context-specific realities.

Key Terms & Definitions

• Inferential Statistics — Using samples to make population inferences.
• Central Limit Theorem — Sample means are normally distributed given large n.
• Standard Error (SE) — Estimated standard deviation of a sampling distribution.
• Type I Error — False positive; rejecting a true null hypothesis.
• Type II Error — False negative; failing to reject a false null hypothesis.
• Power — Probability of correctly rejecting a false null hypothesis.
• t-Distribution — Probability distribution used when σ is unknown and n is small.
• Grey Matter — Neuronal cell bodies and dendrites.
• White Matter — Myelinated axons connecting brain regions.
• MRI — Non-invasive imaging using magnetism to view brain structures.
• BOLD Signal — fMRI measure of blood oxygenation changes.
• Reflexivity — Researcher’s awareness of their influence on study.
• Ontology — Nature of reality.
• Epistemology — Nature of knowledge.
• Emic/Etic — Insider/outsider research perspectives.
• Kaupapa Māori — Indigenous Māori research methodology.
• Talanoa — Pacific conversational qualitative method.

Action Items / Next Steps

• Review practice exam questions and prepare answers, focusing on MRI, research design, and qualitative methods.
• Study the steps and limitations for each MRI method.
• Summarize and memorize definitions and key differences between research paradigms.
• Prepare for qualitative interview question design and understand sampling strategies.