Research Methods Quiz: Experiments Overview

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a characteristic of a one-group posttest only design?

A control group is always necessary for comparison.

Two groups are compared after one group receives treatment.

A treatment is implemented followed by a single measurement of the dependent variable. (correct)

The dependent variable is measured multiple times before and after treatment.

Which factor could potentially affect the results of a one-group pretest-posttest design?

Repeatability of the treatment variable

Participant maturation over time (correct)

Control group dynamics

Random assignment of participants

What distinguishes an interrupted time series design from other designs?

It includes only a single measurement before treatment.

It involves multiple pretest and posttest measurements over time. (correct)

It cannot track changes after treatment implementation.

It always has a control group for comparison.

In a posttest only nonequivalent groups design, what is the key feature?

Comparison is made between two groups with differing exposures to treatment. Signup and view all the answers

Why is the one-group posttest only design considered the weakest type of quasi-experimental design?

It lacks a control group for comparison. Signup and view all the answers

What does generalizability involve in research findings?

Applying findings to larger populations. Signup and view all the answers

In Guba's model, what does dependability refer to?

Whether findings remain the same with similar subjects. Signup and view all the answers

What technique is NOT typically used to demonstrate credibility in research?

Comparison with demographic data. Signup and view all the answers

Which of the following techniques helps in demonstrating confirmability?

Peer examination. Signup and view all the answers

What is a key characteristic of neutrality in Guba's model?

Findings should reflect patterns only from the informants. Signup and view all the answers

What does triangulation involve in research?

Checking results with various raters or measures. Signup and view all the answers

What does stepwise replication help to demonstrate in research?

The dependability of research conclusions. Signup and view all the answers

Which of the following best describes transferability?

The relevance of findings to contexts outside the research setting. Signup and view all the answers

What does a Pearson correlation coefficient of 0 indicate?

No correlation Signup and view all the answers

What indicates a negative correlation between two variables?

Higher scores on one variable are associated with lower scores on the other Signup and view all the answers

Which problem is described when two variables appear correlated due to a third variable?

Third variable problem Signup and view all the answers

What is the primary purpose of factor analysis?

To organize variables into clusters based on their correlations Signup and view all the answers

In a regression equation, what does the variable 'Y' represent?

The outcome variable being predicted Signup and view all the answers

Which term describes the variable used to make predictions in regression analysis?

Independent variable Signup and view all the answers

What is a correlation matrix used for?

To show the correlation between every possible pair of variables Signup and view all the answers

What is the main distinction between simple regression and multiple regression?

Simple regression only uses one variable to predict, whereas multiple regression uses more than one Signup and view all the answers

What characterizes correlational research?

It assesses the relationship between two variables without controlling extraneous variables. Signup and view all the answers

When might a researcher choose correlational research over experimental research?

When it is impractical or unethical to manipulate the independent variable. Signup and view all the answers

What is internal validity?

The extent to which changes in the independent variable cause observed differences in the dependent variable. Signup and view all the answers

Which type of research is characterized by closely resembling true experiments but lacking full manipulation features?

Quasi-experimental research Signup and view all the answers

Which of the following statements regarding observational research is accurate?

It assesses behavior without interfering or manipulating variables. Signup and view all the answers

In correlational research, how is data typically collected?

Using both quantitative and qualitative measurements without variable manipulation. Signup and view all the answers

Which of the following best describes the nature of data in correlational research?

Variables can be either quantitative or qualitative without manipulation. Signup and view all the answers

What does a scatter plot represent in the context of correlational research?

The relationship between two quantitative variables visually. Signup and view all the answers

What is the main disadvantage of studies without random assignment?

They may be subject to confounding variables. Signup and view all the answers

In a pretest-posttest nonequivalent groups design, which group does not receive the treatment?

The control group Signup and view all the answers

What does the interrupted time-series design emphasize in its methodology?

Collecting measurements at intervals before and after an intervention Signup and view all the answers

What is a primary benefit of the pretest-posttest design with switching replication?

It includes built-in replication and controls for historical effects. Signup and view all the answers

What is the purpose of demonstrating a treatment effect in the switching replication with treatment removal design?

To provide evidence for the efficacy of the treatment over time Signup and view all the answers

What is the primary purpose of pilot testing in research?

To ensure that a new procedure works as planned. Signup and view all the answers

Which type of research is characterized by collecting data before defining the research questions?

Retrospective research Signup and view all the answers

What is a key limitation of a case report in research?

It focuses on a single case without comparative analysis. Signup and view all the answers

In a prospective cohort study, what is the initial condition of the participants?

They are all free of the condition at the start. Signup and view all the answers

What distinguishes case control studies from cohort studies?

Case control studies compare individuals with a condition to those without. Signup and view all the answers

Which of the following best describes compilation research?

Research that integrates data from various studies to address a question. Signup and view all the answers

In a retrospective cohort study, how are participants selected?

By their history of exposure or intervention. Signup and view all the answers

What type of study provides documentation on new or complex interventions but lacks statistical comparison?

Case series Signup and view all the answers

Study Notes

Experiment Definition

A type of study designed to determine if one variable causes a change in another.
Changes in one variable (the independent variable) cause a change in another (the dependent variable).

Independent Variable

The variable being manipulated.

Dependent Variable

The variable being measured.

Conditions

Different levels of the independent variable.

Extraneous Variables

Variables other than the independent and dependent variables.
Anything that changes in a study that's not the IV or DV.

Control

Minimizing extraneous variables.

Independent Variable Manipulation

A change that creates a difference in exposure level.
Requires an active intervention.
Not always possible to manipulate a variable.

Extraneous Variables as Confounding Variables

Extraneous variables that differ on average across levels of the independent variable.

Control Conditions

Participants are not given any treatment.
Placebo control condition: Participants receive a simulated treatment that lacks an active ingredient.
Placebo effect: Participants receiving or perceiving an effect similar to the treatment.

Between-Subjects Experiments

Each participant is tested in only one condition.
Participants are randomly assigned to conditions to ensure groups are similar.
Simpler and quicker than other experiments.
Avoids carryover effects.

Random Assignment

Two criteria: Each participant has an equal chance of being assigned to any condition; each participant is assigned to a condition independently of other participants.

Block Randomization

All conditions occur once in the sequence before any repeats
Conditions occur in a random order within each block.
New participant is assigned to the next condition in the sequence.
Prevents unequal sample sizes.

Matched Groups

Participants in various conditions are matched on the dependent variable and/or other extraneous variables to prevent confounding.
Guarantees that variables aren't confounded across experimental conditions.
Helps control for extraneous variables.

Within-Subjects Experiments

Each participant is tested across all conditions.
Maximizes control of extraneous participant variables.
Removes doubts about causation.

Order Effects

Participants' responses in conditions affected by their order of exposure.

Carryover Effects

The effect of one condition on behavior in later conditions.

Practice Effects

Participants perform better in later conditions due to practice.

Fatigue Effects

Participants perform worse in later conditions due to tiredness or boredom.

Context Effects

Being tested in one condition influences perception or task interpretation in another.

Counterbalancing

Testing different participants in different orders.

Complete Counterbalancing

An equal number of participants complete each possible order of conditions.

Random Counterbalancing

Randomly determining the order of conditions for each participant.

Simultaneous Within-Subjects Designs

Participants make multiple responses in each condition.
Entire set of questions presented in a sequence that mixes the types.

Types of Validity

Internal validity, external validity, construct validity, and statistical validity.

Internal Validity

Extent to which a piece of evidence supports a cause/effect claim within a study.
Experiments, due to their design, are typically high in internal validity.

External Validity

Extent to which study results can be applied outside the study's context.
Generalization across situations, people, stimuli, and times.

Construct Validity

Degree to which a test measures what it claims to measure.

Statistical Validity

Extent to which conclusions drawn from a statistical test are accurate and reliable.

Participant Recruitment

Subject pool: Established group of participants.
Participants in subject pools, and those not can be recruited via multiple methods.

Side Effects of Non-Standardized Procedures

Introducing extraneous variables during a procedure.
Risk is exacerbated by multiple experimenters.
Experimenter expectancy effect: Participants conforming to what's expected of them, which may lead to bias.

Record-Keeping

Experimental logs document unusual events and questions.
Maintaining confidentiality of participants.

Manipulation Checks

A separate measure to confirm the independent variable was successfully manipulated.
Done at the procedure's end to confirm effect, avoid unnecessary attention.

Pilot Testing

Small-scale study to confirm new procedure works as planned.

Research Types

Retrospective research: Data collection before research questions were developed.
Retrospective data examples include: case reports, case studies, case control and cohort studies
Prospective research: Research questions and variables are determined before data collection.
Prospective data examples: cohort studies and randomized controlled trials.
Compilation research: Gathers data from diverse studies to answer clinical questions.
Examples are systematic reviews and meta-analyses.
Case Report/study
Detailed description of a single case/patient
Provides opportunity for reporting rare/unique clinical effects.
Case series: Collection of info gathered on a topic
Case-control: Compare patients with the condition to those without the condition.
Prospective cohort: Group with a shared experience tracked over time.
Retrospective cohort: Tracks groups exposed to an intervention or exposure over time.

Randomized Controlled Trials (RCT)

Gold Standard of experimental research.
At least two groups with the same condition (experimental and control).
Random assignment.

Patient Randomized Treatment Order Trials.

Provide strongest evidence.
Patients receive all interventions (treatment order is randomized).
Patients as their own controls.
Minimizes responsive differences between participants.

Systematic Review

Collects evidence from multiple studies.
Highest standard for clinical decisions.

Meta-Analysis

Combines statistical information from multiple studies.
Similar to systematic reviews, but focuses on statistical combining of results.

Hierarchy of Evidence

Levels compare the strength of an article's findings to others.

Non-Experimental Research

Does not involve manipulating independent variables.
Measures variables as they naturally occur.
Can't provide proofs of causation.
Used when manipulating IV is impossible or unethical.

Correlational Research

Measures two variables.
Attempts to assess relationship without control of extraneous variables.
Non-experimental.

Data Collection in Correlational Research

No manipulation of variables is possible, or not done
No particular importance for how variables are measured

Measurement

Variables can be quantitative or qualitative.
Scatter plots, Pearson's correlation coefficient.

Correlation Coefficient

Ranges from -1 to +1.
0 = no correlation.

Reasons Correlation Doesn't Imply Causation

Directionality problem: Variable X could cause variable Y, or vice versa.
Third-variable problem: A third variable could cause both X and Y.

Complex Correlation

Measures multiple variables to assess their statistical relationships.
Can be visualized using a correlation matrix.

Factor Analysis

Studies relationships among multiple conceptually similar variables.
Clusters variables into smaller sets based on strong correlations.

Regression

Used to predict the value of one variable based on the value of another.
The variable to be used to make a prediction is the predictor variable.
The variable that is being predicted is the outcome variable or criterion variable.

Qualitative Research

In-depth information from a small group.
Conclusions drawn by the researcher.
Global and exploratory in nature.

Quantitative Research

Larger samples.
Results based on statistical analysis.
Specific and focused.

Data Collection

Interviews, focus groups.

Survey Types

Questionnaires, interviews, diaries.

Constructs

Important for survey design; understanding differences among individuals or groups.

Survey Questions

Demographic questions: Open-ended (no specific answer options); closed-ended (specific answer options).
Types of scales: Categorical (nominal), Continuous (interval/ratio), Ranked (ordinal).

Summative and Cumulative Scales

Summative scales: Each item contributes equally to the total score
Cumulative scales: Each item represents a higher level of the attribute being measured.

Likert Scale

Used for rating opinions and attitudes.

Scaling Methods

Semantic differential: Scales opinions between two extremes.
Visual Analog Scale: Measures on a line with anchored extremes.

Guttman Scaling

Cumulative scaling, where items represent an increasing level of the aspect being measured.

Assumptions of Surveys

Absolutes; leading questions; low inference statements; double negatives; bias wording; overlapping categories.
Techniques to improve and reduce social desirability bias.
Example: Catch trials and include positively and negatively keyed items.

Delphi Survey

Consensus-building around a specific issue among experts
Establishing clinical practice norms or guidelines.

Cognitive Model (Survey design)

The stages people go through when interpreting questions and selecting responses, as described in a "model".

Survey Response Effects

Context effects; item order effect; response option effect
Open-ended items, closed-ended items.

Rating Scales

Ordered number of response options.

BRUSO Model

Brief, Relevant, Unambiguous, Specific, and Objective (for survey design/question wording).

One-Group Posttest-Only Designs

Implementation of a treatment and subsequent measurement of a dependent variable.
Weakest type of quasi-experimental design due to lack of control.

One-Group Pretest-Posttest Designs

Measurement of a dependent variable before and after a treatment.
Can be interpreted as a quasi-experimental design based on interpretation.
Other factors such as history, maturation, testing, instrumentation, regression to the mean, or spontaneous remission may also create changes in the dependent variable.

Interrupted Time Series Design

Multiple measurements of a variable over time, before and after an intervention.

Posttest-Only Nonequivalent Groups Design

Comparing a treatment group that was exposed to an intervention, with a control group.

Multiple-Treatment Reversal Design

Introducing multiple treatments in phases and tracking the effect of each.
Reversing treatments to get a better understanding.

Multiple Baseline Designs

Introducing treatments in phases and tracking the effect across different participants, behaviors or settings.

Hypothesis Testing

Using samples to draw conclusions about a population.
Sample statistics are estimations that are influenced by random variability.

Null Hypothesis Testing

Formally deciding between two possibilities for a statistical relationship in a sample.
H0 = No relationship in the population / random, sampling error is the sole reason and not a real relationship.
Ha = A real relationship in the population is present and not sampling error.

Critical Values and Rejection Region

Statistical values which if an observed value is beyond it, the null hypothesis is rejected in favor of the alternate hypothesis.

Directional/Non-Directional Hypotheses

Directional hypotheses: There is a specific direction of expected difference
Non-directional hypotheses: Only that there will be a difference is what is tested.

Sample Size and Relationships

Higher samples generally produce results that are more likely true relationships.

t-Tests

Comparing the means of two unrelated groups.
Comparing the mean of a single sample with a known/hypothetical population mean.
Comparing the means of two related scores from the same sample group.

ANOVA

Comparing the means of three or more independent groups.

Post Hoc Tests

Used after an ANOVA to determine which specific group means are significantly different.

Repeated Measures ANOVA

Comparing differences among scores for the same participant over multiple measurements.

Statistical Power

Probability of rejecting the null hypothesis if a relationship is present.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on key concepts of experimental research methods, including the definitions of independent and dependent variables, control conditions, and the role of extraneous variables. Learn how manipulation and control are essential in determining causation in experiments.