Lecture Notes: Quantitative Research Methods Flashcards

A comprehensive set of Q&A flashcards covering key concepts from the lecture notes on quantitative research methods, including research design, validity, reliability, measurement, theory, and statistical reasoning.

What is the difference between a research question and a research hypothesis?

A research question is a broad, general inquiry; a hypothesis is a specific, testable prediction about the relationship between variables, usually stated in an operationalized form (H1).

In a quantitative depression study, which variable is typically the independent variable and which is the dependent variable?

Independent variable: level of depression (predictor); Dependent variable: academic performance (outcome, e.g., GPA or year-1 average).

What are the four aims of the scientific method in behavioral research as described in the notes?

Describe reality (descriptive), predict future outcomes (prediction), understand cause-and-effect relationships (causal understanding), and explain/achieve control over phenomena (explanation and manipulation) using empirical testing.

What does Popper’s principle of falsifiability require of a theory?

A theory must be testable and potentially falsifiable; it should make predictions that could be proven false by evidence.

What is the file drawer (publication bias) problem?

Non-significant results are less likely to be published, leading to a biased overall estimate of effects in the literature.

What is inductive reasoning in research?

Reasoning from specific observations to general conclusions or theories.

What is deductive reasoning in research?

Reasoning from a general theory to specific hypotheses or predictions.

What is a paradigm in science?

A broad worldview or framework that guides what questions are asked and which methods are used; can shift during scientific revolutions (Kuhn).

What is the difference between an axiom, a paradigm, and a theory?

Axiom: a basic, assumed principle; Paradigm: a framework guiding research; Theory: an organized set of propositions explaining phenomena and making testable predictions.

What is Occam’s razor in theory selection?

Prefer simpler, more general theories with fewer assumptions when explanations are otherwise comparable.

What is operationalization?

Translating a theoretical construct into measurable variables by specifying exact procedures or instruments for measurement.

What is a construct in research terms?

An abstract concept (e.g., intelligence, motivation) that researchers aim to measure or manipulate.

What is the difference between nominal and operational definitions?

Nominal definition labels a concept at a theoretical level; operational definition specifies how the concept will be measured or manipulated in a study.

What is construct validity and its subtypes?

Construct validity is the extent a test measures the intended construct. Subtypes include face validity, content validity, criterion validity (predictive/concurrent/postdictive), convergent validity, and discriminant validity.

What is face validity?

The extent to which a measurement appears to measure what it is supposed to measure, based on subjective judgment.

What is content validity?

The extent to which the items of a test cover all aspects of the domain of the construct.

What is criterion validity and its types?

Criterion validity assesses whether a measure relates to a relevant outcome; predictive (future), concurrent (present), and postdictive (past).

What is convergent validity?

Measures that should be related are indeed related.

What is discriminant validity?

Measures that should not be related are not related.

What is MTMM matrix?

Multi-Trait Multi-Method matrix used to evaluate convergent and discriminant validity across multiple traits and measurement methods.

What is reliability in measurement?

Consistency or stability of a measure across time, items, or raters.

Name four common forms of reliability.

Test-retest reliability; parallel/equivalent forms reliability; internal consistency (Cronbach’s alpha); inter-rater reliability.

What is Cronbach’s alpha?

A statistic that measures the internal consistency of a scale; higher values indicate that items on the scale measure the same construct.

What is split-half reliability with Spearman-Brown correction?

Split the test into two halves, compute the correlation between halves, and apply the Spearman-Brown correction to estimate full-scale reliability.

What is inter-rater reliability?

The degree to which different raters or observers give consistent assessments or scores.

What is measurement error and its two components?

Measurement error comprises systematic (constant) error and random (unpredictable) error; reliability concerns the random component, while validity concerns accuracy.

How are reliability and validity related?

They are related but distinct: a measure can be reliable but not valid; validity requires that the measure assess the intended construct, not just be consistent.

What is internal validity?

The extent to which a study establishes a causal relationship between the manipulated variable and the outcome, free from confounds.

What is external validity?

The extent to which study findings generalize to other populations, settings, times, and measures.

What is ecological validity?

A form of external validity focusing on how findings generalize to real-world, natural settings.

List common threats to internal validity.

History, maturation, instrumentation, testing, regression to the mean, selection bias, mortality (attrition), and diffusion or contamination (intervention effects crossing groups).

What is the Solomon four-group design?

An experimental design that crosses pretesting (pretest vs none) with treatment vs control to control for pretest and testing effects.

What is randomization in experiments?

Random assignment of participants to conditions to minimize preexisting differences and distribute confounds evenly.

What is counterbalancing?

A technique to control order effects by varying the sequence of conditions; can be complete, partial (Latin square), or other schemes.

What is a within-subjects design?

The same participants experience all conditions of the independent variable.

What is a between-subjects design?

Different participants are assigned to each condition of the independent variable.

What is a factorial design?

An experimental design with two or more independent variables (e.g., 2x3x2), used to study main effects and interactions.

What is a main effect?

The overall effect of one independent variable across levels of other independent variables.

What is an interaction effect?

The effect of one independent variable depends on the level of another independent variable.

What is random sampling vs random assignment?

Random sampling refers to how participants are drawn from the population; random assignment refers to how those participants are allocated to experimental groups.

What is the difference between a confound and an artifact?

A confound is an extraneous variable that explains the observed effect and is related to the manipulation; an artifact is an extraneous effect not central to the phenomenon and may be separable.

What threats to internal validity does maturation refer to?

Participants change over time due to aging or development, which can confound the effect of the manipulation.

What is a blind experiment?

An experimental design where the researcher (and/or participants) are unaware of the treatment condition to prevent expectancy effects.

What is the difference between internal and external validity in terms of design quality?

Internal validity concerns causal conclusions within the study; external validity concerns generalizability of findings beyond the study.

What is statistical conclusion validity?

The degree to which conclusions about the relationship among variables from statistical analyses are sound; relates to Type I and Type II error risks, alpha, beta, and power.

What is Type I error and Type II error?

Type I: false positive (concluding an effect exists when it does not); Type II: false negative (failing to detect a true effect).

What is statistical power?

The probability of correctly rejecting a false null hypothesis (1 - beta); higher power reduces Type II error and increases the chance of detecting real effects.

What is the purpose of replication in research?

To test the reliability and external validity of findings by reproducing results in different samples, settings, or methods.

What is a confound in experimental research and how is it addressed?

A variable that provides an alternative explanation for an observed effect; addressed through randomization, control conditions, and careful design to isolate the causal variable.

What is counterbalancing’s purpose in experiments?

To control for order and practice effects so that observed differences reflect the manipulated variable rather than sequence effects.

What is the difference between an experimental and a quasi-experimental design?

Experimental designs use random assignment and control; quasi-experiments lack random assignment and are more prone to selection biases but are often used in natural settings.

What is ecological validity’s relationship to real-world research?

It refers to how well findings generalize to real-life contexts and everyday settings outside the lab.

What is the purpose of ethical considerations in experiments?

To protect participants from harm, ensure informed consent, and maintain integrity and fairness in research practices.

What is a mediator variable?

A variable that explains the mechanism through which an independent variable influences a dependent variable, creating an indirect effect.

What is a moderator variable?

A variable that changes the strength or direction of the relationship between an independent and a dependent variable.

What is the difference between correlation and causation?

Correlation indicates a relationship between variables, but does not prove that one causes the other; causation requires experimental manipulation and ruling out confounds.

What is a significance level (alpha) commonly set at in behavioral research?

A common threshold is 0.05, representing a 5% risk of a Type I error.

What is a p-value?

The probability of obtaining results at least as extreme as observed, assuming the null hypothesis is true; used to decide whether to reject H0.

What is the importance of measurement levels (nominal, ordinal, interval, ratio)?

Different levels determine suitable analyses and the type of mathematical operations that are meaningful for the data.

What is a pretest-posttest design with randomization called?

A design where participants are measured before and after a manipulation, with random assignment to conditions to control for confounds.

What is 'null hypothesis significance testing' (NHST)?

A framework in which the null hypothesis is tested against data to determine if there is evidence to reject it in favor of an alternative.

Why is replication crucial for science?

It tests the reliability and robustness of findings across samples, settings, and methods, helping to confirm or refine theories.