Design or Disaster?
The defining feature that separates a true experiment from a quasi-experiment.
What is random assignment?
Confidence that the independent variable caused the observed change.
What is internal validity?
A correlation coefficient tells us these two things.
What are strength and direction?
The variable manipulated by the researcher.
What is the independent variable?
A researcher randomly assigns students to CBT or control and compares posttest scores. This design is what?
What is experimental research?
If a researcher manipulates an intervention but uses intact classrooms, the design is what
What is quasi-experimental?
When groups differ before the intervention even begins.
What is selection bias?
r = -.72 indicates what kind of relationship?
What is a strong negative relationship?
The measured outcome variable.
What is the dependent variable?
A study claims “the intervention caused improvement” but has no control group. The major flaw is what?
What is weak internal validity?
A study measuring stress and GPA at the same time using r = -.48 is what design?
What is correlational research?
When participants improve simply because they grow or mature over time.
What is maturation?
The two major reasons correlation cannot establish causation.
What are the third-variable problem and directionality problem?
Turning “depression” into “score on the PHQ-9” is called what?
What is operationalization?
A study conducted only in one affluent suburban school primarily threatens what?
What is external validity?
Groups formed by existing diagnosis (e.g., ADHD vs. non-ADHD) compared on test scores is what design?
What is causal-comparative research?
When taking the pretest boosts posttest performance artificially.
What is testing effect?
If N = 12 and r = .60, what statistical concern should you raise?
What is low statistical power/small sample size concern?
Variables that are controlled to reduce confounding influence are called what?
What are control variables?
If researchers change assessment tools mid-study, what threat appears?
What is instrumentation threat?
Tracking the same group of students’ anxiety scores over 5 years without manipulation is what type of design?
What is longitudinal descriptive research?
When participants disappear unevenly across groups like academic ghosts.
What is attrition (mortality)?
A statistically significant correlation with a tiny effect size lacks what?
What is practical significance?
When an outside variable influences both IV and DV, creating a false impression of causality.
What is a confounding variable?
If teachers in the intervention group also receive additional coaching, what methodological issue arises?
What is a confounding variable due to differential treatment?