Master the Art and Science of Hypothesis Development, Formation, and Testing Across All Research Paradigms
🎯 Understanding Research Hypotheses
A research hypothesis represents a specific, testable prediction about expected relationships between variables, established before data collection begins. Unlike research questions that explore "what" phenomena exist, hypotheses predict "what will happen" based on theoretical understanding and existing evidence.
🔬 Core Characteristics of Research Hypotheses
Predictive Nature: Makes specific predictions about relationships or outcomes
Testability: Can be empirically investigated using available methods
Falsifiability: Can potentially be proven wrong through evidence
Theoretical Grounding: Based on existing literature and logical reasoning
Specificity: Clearly defined variables and predicted relationships
Temporal Priority: Formulated before data collection begins
📈 Distinguishing Hypotheses from Related Concepts
Research Questions
Purpose: Pose open-ended inquiries that guide investigation
Example: "What is the relationship between sleep duration and academic performance?"
Research Objectives
Purpose: Outline how studies will be conducted and goals achieved
Example: "To compare academic achievement between students sleeping different amounts"
Research Hypotheses
Purpose: Propose tentative answers with testable predictions
Example: "Students sleeping at least 8 hours nightly will achieve significantly higher grades than those sleeping less than 8 hours"
Forecasting
Purpose: Make future predictions without explanatory mechanisms
Example: "Student grades will improve next semester"
📊 Complete Taxonomy of Hypothesis Types
Statistical Framework
🔹 Null Hypothesis (H₀)
Assumes no relationship exists between variables; observed differences result from random chance.
🔹 Alternative Hypothesis (H₁ or Hₐ)
Proposes that significant relationships or differences do exist.
Example:
H₀: There is no difference in test scores between online and in-person learning
H₁: There is a significant difference in test scores between online and in-person learning
Directional Framework
🔹 Directional Hypotheses
Specify the expected direction of relationships or differences, predicting whether one group will score higher, lower, or show positive/negative correlations.
🔹 Non-directional Hypotheses
Acknowledge that differences exist without specifying direction.
Directional: "Group A will score significantly higher than Group B" Non-directional: "There will be a significant difference between Group A and Group B"
Complexity Framework
🔹 Simple Hypotheses
Examine relationships between single independent and dependent variables.
🔹 Complex Hypotheses
Address multiple variables simultaneously, including interactions.
Simple: "Exercise improves mood" Complex: "Exercise frequency and intensity interact to predict mood, moderated by age and baseline fitness"
Causal Framework
🔹 Associative Hypotheses
Describe correlational relationships without implying causation.
🔹 Causal Hypotheses
Propose direct cause-and-effect mechanisms.
Associative: "Study time is positively correlated with exam scores" Causal: "Increased study time causes higher exam scores"
🎓 Hypotheses Across Research Paradigms
1Positivist Research
Places hypotheses at the center of investigation, using them to test established theories through deductive reasoning. Emphasizes highly structured, specific hypotheses tested through controlled experiments with statistical methods.
Key Characteristics:
Deductive approach from theory to hypothesis to testing
Null-alternative hypothesis frameworks
Predetermined significance criteria
Objective reality testing
Generalizable findings focus
2Interpretivist Research
Uses hypotheses more flexibly, often developing tentative propositions during investigation rather than before. Emphasizes understanding subjective meanings and social constructions.
Key Characteristics:
Flexible hypothesis development
Sensitizing concepts rather than rigid predictions
Emerging propositions from data analysis
Contextual understanding focus
Participant perspective integration
3Pragmatist Research
Adopts flexible hypothesis use depending on research questions and practical needs. Mixed methods investigations may combine deductive hypothesis testing with inductive theory generation.
Key Characteristics:
Method-question matching approach
Quantitative predictions with qualitative explanations
Practical utility emphasis
Sequential or concurrent hypothesis use
Problem-solving orientation
4Critical Theory Research
Develops hypotheses related to power structures, social justice, and transformative outcomes. Often challenges dominant assumptions while proposing emancipatory alternatives.
Key Characteristics:
Power structure examination
Social justice focus
Transformative outcome hypotheses
Normative claims inclusion
Action-oriented validation
🧠 Systematic Hypothesis Formation and Development
⚠️ When to Use vs. Avoid Hypotheses
✅ Use Hypotheses When:
Conducting experimental or quasi-experimental research
Feasible: Can be investigated within available resources and constraints
Interesting: Appeals to the scientific community and advances knowledge
Novel: Addresses knowledge gaps or provides new perspectives
Ethical: Meets research standards and protects participants
Relevant: Addresses important practical or theoretical problems
📋 Multiple Methods for Generating Research Hypotheses
🔬 Deductive Approaches
Theory-driven method: Begin with established theories or frameworks to derive specific testable predictions.
Process Steps:
Identify relevant theoretical frameworks
Extract key propositions and relationships
Operationalize theoretical constructs
Derive specific testable predictions
Formulate null and alternative hypotheses
Example:
Theory: Social Cognitive Theory
Proposition: Self-efficacy influences performance
Hypothesis: "Students with higher self-efficacy scores will achieve better academic performance than those with lower scores"
🔍 Inductive Approaches
Data-driven method: Start with observations, data patterns, or empirical findings to generate explanatory hypotheses.
Process Steps:
Collect preliminary observational data
Identify patterns and relationships
Generate tentative explanations
Develop testable propositions
Refine hypotheses based on additional data
Example:
Observation: Students using certain study apps show improved retention
Pattern: Gamified elements correlate with engagement
Hypothesis: "Gamified study applications will result in higher retention rates compared to traditional study methods"
🧩 Abductive Reasoning
Best-explanation method: Combines deductive and inductive elements to generate hypotheses that best explain available evidence.
Process Steps:
Gather diverse evidence sources
Consider multiple competing explanations
Evaluate explanatory power of each
Select most plausible explanation
Formulate testable hypotheses
Example:
Evidence: Inconsistent results across studies on meditation and stress
Competing explanations: Type of meditation, duration, individual differences
Best explanation: Meditation type moderates stress reduction effects
Hypothesis: "Mindfulness meditation will show greater stress reduction than concentration meditation"
🔗 Analogical Methods
Cross-domain application: Apply successful theories from related domains to new contexts.
Process Steps:
Identify successful theories in related fields
Map structural similarities between domains
Adapt theoretical relationships to new context
Test boundary conditions and limitations
Formulate domain-specific hypotheses
Example:
Source domain: Flow theory in sports psychology
Target domain: Online learning environments
Analogical hypothesis: "Students in optimally challenging online courses will experience higher engagement and better performance"
📚 Comprehensive Sources for Hypothesis Development
📖 Academic Literature
Peer-reviewed research, meta-analyses, theoretical papers, and conference proceedings
📊 Empirical Evidence
Pilot studies, previous research findings, observational data, and archival research
🧠 Theoretical Sources
Established theories, conceptual frameworks, mathematical models, and interdisciplinary perspectives
🛠️ Practical Sources
Professional experience, real-world problems, policy questions, and expert consultation
Colleague Review: Seek feedback before data collection
Structured Checklists: Use systematic evaluation criteria
Expert Feedback: Consult domain specialists
Pilot Testing: Verify measurement approaches
Iterative Refinement: Improve based on feedback
Documentation: Record development process
📝 Hypothesis Format Options
If-Then Format:
"If students receive personalized feedback, then their performance will improve more than students receiving generic feedback."
Correlational Format:
"There will be a positive correlation between social media usage time and reported feelings of loneliness among adolescents."
Group Difference Format:
"Participants in the intervention group will show significantly greater improvement in anxiety symptoms compared to the control group."
Effect Statement Format:
"Mindfulness training will result in reduced cortisol levels and improved stress management scores."
⚠️ Common Hypothesis Writing Pitfalls
Unclear Variable Definitions: Using vague terms without operational definitions
Excessive Breadth: Trying to address too many variables or relationships
Lack of Theoretical Foundation: Making arbitrary predictions without justification
Circular Reasoning: Using causes and effects that refer to identical concepts
Untestable Propositions: Making claims that cannot be empirically investigated
Bias and Opinion: Including personal beliefs rather than evidence-based predictions
🎯 Foundation Principles of Statistical Hypothesis Testing
Statistical hypothesis testing provides a formal decision-making framework for evaluating claims about population parameters using sample data. The process centers on comparing null hypotheses (stating no effect exists) with alternative hypotheses (proposing specific effects or relationships).
Key Components
Test Statistics: Measure deviation from null hypothesis
P-values: Probability of results if null is true
Significance Levels (α): Threshold for rejection (usually 0.05)
Critical Regions: Values leading to null rejection
Decision Rules: Systematic decision criteria
Error Types
Type I Error: False positive (α level controls)
Type II Error: False negative (β level)
Statistical Power: 1-β (ability to detect true effects)
Effect Size: Practical significance measure
📊 Parametric Testing Procedures
📈 t-Tests
Purpose: Compare means for normally distributed continuous data
Types and Applications:
One-sample t-test: Compare sample mean to known value
Independent samples t-test: Compare means between two groups
Paired samples t-test: Compare related measurements
Formula (One-sample):
t = (x̄ - μ₀) / (s/√n)
Assumptions:
• Normal distribution or n ≥ 30
• Random sampling
• Independent observations
📊 Analysis of Variance (ANOVA)
Purpose: Compare means across three or more groups
MANOVA Test Statistics:
• Wilks' Lambda
• Pillai-Bartlett Trace
• Hotelling's T²
• Roy's Largest Root
🔄 Non-Parametric Alternatives
📝 When to Use Non-Parametric Tests
Non-parametric tests are robust alternatives when parametric assumptions are violated, including non-normal distributions, ordinal data, small sample sizes, or extreme outliers that cannot be addressed through transformation.
👥 Independent Groups
Mann-Whitney U Test
Replaces: Independent samples t-test
Procedure: Combines groups, ranks all observations, compares rank sums
When to Use:
• Non-normal distributions
• Ordinal data
• Small sample sizes
• Extreme outliers present
🔗 Related Groups
Wilcoxon Signed-Rank Test
Replaces: Paired samples t-test
Procedure: Ranks difference scores, tests median difference against zero
Concurrent Triangulation: Simultaneous data collection and comparison
Embedded Design: One method supports the other
Integration Tools:
• Side-by-side comparison tables
• Joint displays showing convergence/divergence
• Meta-inferences combining insights
• Transformation of qualitative to quantitative data
🎯 Advanced Testing Considerations
⚡ Power Analysis
Statistical Power: Probability of correctly rejecting false null hypotheses (typically ≥0.80)
A Priori Power Analysis:
Calculate required sample sizes before data collection
Prevents underpowered studies
Requires effect size estimates
Consider practical constraints
Sample Size Examples (α=0.05, power=0.80):
• Medium effect (d=0.5): ~64 per group for t-test
• Small effect (d=0.2): ~393 per group
• Large effect (d=0.8): ~26 per group
Optional Stopping: Ending collection based on significance
Best Practices:
• Pre-register analysis plans
• Report all tests conducted
• Distinguish planned from exploratory
• Use appropriate corrections
📋 Step-by-Step Hypothesis Development Workflow
1Foundation Building
🎯 Problem Identification
Identify specific research problems that are empirically investigable
Ensure theoretical significance and practical relevance
Assess feasibility within available resources
Consider ethical implications and requirements
📚 Literature Review Process
Search Strategy
Develop comprehensive search terms
Use multiple databases and sources
Include grey literature and recent publications
Document search process for replication
Analysis Focus
Identify existing theories and frameworks
Note empirical findings and patterns
Recognize knowledge gaps and contradictions
Examine methodological approaches
❓ Research Question Development
Quality Criteria for Research Questions:
• Specific enough for targeted investigation
• Broad enough to generate meaningful knowledge
• Empirically tractable with available methods
• Theoretically grounded and significant
Example Progression:
Too broad: "How does technology affect learning?"
Better: "How do interactive digital tools affect student engagement?"
Optimal: "Do students who attend more interactive online lectures show better exam results?"
2Theoretical Framework Construction
🧠 Conceptual Model Development
Select or develop frameworks that logically connect variables
Justify predicted relationships based on theory
Consider alternative explanations and competing theories
Map causal pathways and potential mediators/moderators
🔍 Variable Identification and Definition
Independent Variables
Manipulated factors (experimental)
Examined factors (observational)
Predictor variables (correlational)
Clear operational definitions
Dependent Variables
Measured outcomes
Criterion variables
Response measures
Reliable measurement procedures
Control Variables
Potential confounding factors
Demographic characteristics
Environmental conditions
Baseline measurements
3Hypothesis Formulation
📝 Initial Prediction Development
Transform theoretical predictions into testable statements
Use operational definitions for all constructs
Follow "if-then" formats for clarity
Specify expected relationship directions when justified
⚖️ Null and Alternative Hypothesis Formation
Statistical Hypothesis Template:
Research Hypothesis:
"Students receiving personalized feedback will show greater improvement in writing quality than students receiving generic feedback."
Null Hypothesis (H₀):
"There is no difference in writing quality improvement between students receiving personalized versus generic feedback."
Alternative Hypothesis (H₁):
"Students receiving personalized feedback will show significantly greater improvement in writing quality than students receiving generic feedback."
Hierarchical Structure: Nested data considerations
🔧 Violation Remedies
Decision Tree for Assumption Violations:
Non-Normal Data:
• Try data transformation (log, square-root, reciprocal)
• Use robust statistical methods
• Apply non-parametric alternatives
• Bootstrap or permutation tests
Unequal Variances:
• Welch's correction for t-tests
• White's robust standard errors
• Transformation to stabilize variance
• Non-parametric alternatives
Dependence Issues:
• Mixed-effects models for hierarchical data
• Time series analysis for temporal dependencies
• Cluster-robust standard errors
• Generalized estimating equations (GEE)
2Test Selection and Execution
🎯 Method Selection Criteria
Decision Support Framework
Click a button above to explore the decision framework for statistical test selection.
📊 Execution Checklist
Verify data entry accuracy and completeness
Confirm appropriate statistical software setup
Double-check variable coding and transformations
Implement planned analysis with exact specifications
Document all analysis decisions and modifications
Save analysis scripts for reproducibility
3Results Interpretation and Reporting
📈 Statistical Significance Assessment
P-value Interpretation
Compare to predetermined α level (usually 0.05)
Avoid interpreting as "probability hypothesis is true"
Descriptive Statistics:
"Participants in the intervention group (M = 85.2, SD = 12.4, n = 45) scored higher than control group participants (M = 78.6, SD = 11.8, n = 42)."
Inferential Results:
"An independent samples t-test revealed a statistically significant difference between groups, t(85) = 2.47, p = .015, d = 0.54 (95% CI [0.11, 0.97])."
Interpretation:
"The intervention group showed a medium-sized improvement in performance compared to the control group, supporting the research hypothesis."
4Hypothesis Decision and Implications
⚖️ Decision Framework
Reject Null Hypothesis
Statistical significance achieved (p < α)
Effect size suggests practical importance
Results support alternative hypothesis
Consider confidence intervals and precision
Fail to Reject Null
Insufficient evidence against null (p ≥ α)
Consider statistical power and sample size
Examine effect size for practical significance
Avoid concluding "no effect" without power analysis
🔮 Future Research Implications
Identify limitations and boundary conditions
Suggest replication studies and extensions
Consider alternative explanations and mechanisms
Propose methodological improvements
🎭 Qualitative Hypothesis Testing Workflow
1Pattern Development and Prediction
🎯 Theoretical Pattern Specification
Derive clear propositions from existing theories
Specify expected relationships between qualitative variables
Consider alternative theoretical explanations
Document prediction rationale and assumptions
Pattern Specification Example:
Theory: Technology Acceptance Model Context: Remote work adoption during pandemic
Predicted Pattern:
• Perceived usefulness → Positive attitudes
• Ease of use → Increased adoption intention
• Social influence → Behavioral change
• Technical support → Sustained usage
2Data Collection and Analysis
📊 Systematic Data Gathering
Interview Protocol
Semi-structured questions aligned with theoretical predictions
Probes for disconfirming evidence
Consistent format across participants
Audio recording and transcription procedures
Observational Methods
Structured observation protocols
Field notes with theoretical focus
Multiple observation contexts
Inter-rater reliability procedures
🔍 Pattern Identification Process
Initial Coding: Open coding of all data
Focused Coding: Identify patterns related to predictions
Theoretical Coding: Connect codes to theoretical framework
Disconfirming Evidence: Actively search for contradictions
3Pattern Matching and Validation
🔄 Comparison Process
Full Pattern Matching
Compare multiple competing theories
Rigid comparison criteria
Determine best explanatory fit
Document decision rationale
Flexible Pattern Matching
Allow theory-data interaction
Continuous hypothesis refinement
Adaptive comparison criteria
Emergent pattern recognition
✅ Validation Strategies
Member checking with participants
Peer debriefing with colleagues
Triangulation across data sources
Negative case analysis
Audit trail documentation
Reflexivity and bias examination
4Cross-Case Analysis Integration
📋 Systematic Case Comparison
Strategic case selection varying on theoretical dimensions
Consistent within-case analysis procedures
Systematic cross-case pattern identification
Visual displays and matrices for comparison
📊 Analysis Tools and Techniques
Cross-Case Analysis Matrix Example:
Case
Predictor A
Predictor B
Outcome
Pattern Match
Organization 1
High
High
Successful
✓ Confirmed
Organization 2
Low
High
Partial
? Mixed
Organization 3
High
Low
Failed
✗ Disconfirmed
🛠️ Intelligent Hypothesis Testing Method Selector
This interactive tool helps you select the most appropriate hypothesis testing method based on your study characteristics, data type, and research objectives.
📋 Study Characteristics Input
📊 Recommended Testing Method
Please fill in the study characteristics above to get personalized method recommendations.
🎯 Quick Decision Trees
📊 Statistical Tests
Quick guide for selecting appropriate statistical hypothesis tests
🎭 Qualitative Methods
Decision support for qualitative hypothesis testing approaches
🔀 Mixed Methods
Integration strategies for comprehensive hypothesis testing
⚡ Power Analysis
Sample size and effect size determination guidance
📊 Statistical Tests Decision Tree
Step-by-Step Test Selection
Step 1: Identify Data Type and Objective
One Sample
Continuous + Normal: One-sample t-test
Continuous + Non-normal: Wilcoxon signed-rank
Categorical: Chi-square goodness-of-fit
Two Groups
Independent + Normal: Independent t-test
Independent + Non-normal: Mann-Whitney U
Related + Normal: Paired t-test
Related + Non-normal: Wilcoxon signed-rank
Multiple Groups
Independent + Normal: One-way ANOVA
Independent + Non-normal: Kruskal-Wallis
Related + Normal: Repeated measures ANOVA
Multiple factors: Factorial ANOVA
Relationships
Linear + Normal: Pearson correlation
Monotonic: Spearman correlation
Prediction: Linear/Multiple regression
Categorical: Chi-square independence
🎭 Qualitative Hypothesis Testing Guide
Pattern Matching
Best for: Testing specific theoretical predictions
Clear theoretical framework exists
Specific patterns can be predicted
Competing theories to compare
Structured data collection possible
Cross-Case Analysis
Best for: Generalizable pattern identification
Multiple cases available
Systematic comparison needed
Replication logic applicable
Variation in key variables
Explanation Building
Best for: Causal mechanism investigation
How/why questions central
Iterative theory development
Complex causal relationships
Rich case study data
Grounded Theory
Best for: Theory generation from data
Limited existing theory
Inductive approach preferred
Process understanding needed
Constant comparative method
🔀 Mixed Methods Integration Guide
Sequential Designs
Sequential Explanatory
QUAN → qual
Start with quantitative hypothesis testing
Use qualitative to explain unexpected results
Explore significant findings in depth
Understand mechanisms behind effects
Sequential Exploratory
QUAL → quan
Start with qualitative exploration
Generate hypotheses from findings
Test hypotheses quantitatively
Validate instruments and measures
Concurrent Designs
Convergent Parallel
QUAN + QUAL
Simultaneous data collection
Independent analysis
Compare and integrate results
Look for convergence and divergence
Embedded Design
QUAN(qual) or QUAL(quan)
One method supports the other
Secondary method provides context
Enhance understanding of results
Address different research questions
⚡ Power Analysis and Sample Size Guide
Power Analysis Calculator Concepts
Required Inputs
Effect Size: Expected magnitude of difference
Alpha Level: Type I error rate (usually 0.05)
Power: Desired probability of detecting effect (usually 0.80)
Test Type: Statistical test to be used
Effect Size Guidelines
Small: d = 0.2, r = 0.1, η² = 0.01
Medium: d = 0.5, r = 0.3, η² = 0.06
Large: d = 0.8, r = 0.5, η² = 0.14
Custom: Based on previous research or pilot data
Sample Size Examples (α = 0.05, Power = 0.80):
Independent t-test:
• Small effect (d = 0.2): 393 per group
• Medium effect (d = 0.5): 64 per group
• Large effect (d = 0.8): 26 per group
One-way ANOVA (3 groups):
• Small effect (f = 0.1): 969 total
• Medium effect (f = 0.25): 159 total
• Large effect (f = 0.4): 66 total
💡 Real-World Hypothesis Examples
Explore comprehensive examples of hypothesis development and testing across different research domains and methodologies.
🧠 Psychology Research
Social media usage and mental health: A mixed-methods investigation
🎓 Educational Research
Online learning effectiveness: Experimental design with multiple hypotheses
🏥 Health Sciences
Exercise intervention for depression: Randomized controlled trial
💼 Business Research
Remote work productivity: Organizational case study approach
💻 Technology Research
AI chatbot user acceptance: Technology adoption model testing
🏛️ Social Sciences
Community intervention program: Quasi-experimental evaluation
🧠 Psychology Research Example
Social Media Usage and Mental Health: A Mixed-Methods Investigation
1Research Context and Objectives
Background: Increasing concern about social media's impact on adolescent mental health, with conflicting findings in the literature.
Research Questions:
1. Is there a relationship between daily social media usage time and depression/anxiety symptoms?
2. What are the mechanisms through which social media affects mental health?
3. Do individual differences moderate these relationships?
2Hypothesis Development
Quantitative Hypotheses
H1: Higher daily social media usage will be positively correlated with depression symptoms (r > 0.20).
H2: Higher daily social media usage will be positively correlated with anxiety symptoms (r > 0.15).
H3: Self-esteem will mediate the relationship between social media usage and mental health outcomes.
H4: The relationship will be stronger for females than males.
Qualitative Propositions
P1: Adolescents will describe social comparison as a key mechanism linking social media to negative feelings.
P2: Fear of missing out (FOMO) will emerge as a central theme in social media experiences.
P3: Positive social media experiences will involve authentic connection and support.
3Method and Results
Quantitative Phase
Participants: 450 adolescents (13-18 years)
Measures: Social media usage tracking, PHQ-9 (depression), GAD-7 (anxiety), Rosenberg Self-Esteem Scale
Pattern Matching Results:
• P1: Strongly confirmed - social comparison central theme
• P2: Confirmed - FOMO prominent in 18/24 interviews
• P3: Extended - support networks and creative expression identified
4Integration and Implications
Mixed Methods Integration: Quantitative results supported by qualitative insights. Social comparison emerged as key mechanism, with self-esteem as mediator confirmed through both statistical analysis and participant narratives.
🎯 Key Findings and Implications
Convergent Evidence: Both quantitative and qualitative data support negative impact hypothesis
Mechanism Identification: Social comparison and FOMO as primary pathways
Individual Differences: Gender and self-esteem as important moderators
Intervention Targets: Focus on healthy usage patterns and self-esteem building
🎓 Educational Research Example
Online Learning Effectiveness: Experimental Design with Multiple Hypotheses
1Study Design and Context
Context: University-level statistics course comparing traditional lecture, interactive online, and hybrid delivery methods.
Experimental Design:
• Randomized controlled trial
• Three conditions: Traditional (n=85), Online (n=82), Hybrid (n=88)
• Same content, instructor, and assessment
• 12-week semester duration
2Multiple Hypothesis Framework
Learning Outcomes
H1: Hybrid learning will result in higher final exam scores than traditional or online-only methods.
H2: Online-only learning will show lower performance than traditional for complex problem-solving items.
Engagement and Satisfaction
H3: Interactive online elements will increase student engagement compared to traditional lectures.
H4: Student satisfaction will be highest in hybrid condition due to flexibility and interaction.
Moderating Variables
H5: Technology self-efficacy will moderate the relationship between delivery method and outcomes.
H6: Learning style preferences will interact with delivery method effectiveness.
3Statistical Analysis Plan
Primary Analysis:
• One-way ANOVA for group comparisons
• Post-hoc tests with Bonferroni correction
• Effect size calculation (eta-squared)
Secondary Analysis:
• Two-way ANOVA for interaction effects
• Regression analysis for continuous moderators
• Planned contrasts for specific comparisons
4Results and Hypothesis Testing
Supported Hypotheses
H1: ✓ Hybrid > Traditional > Online, F(2,252) = 8.45, p < 0.001, η² = 0.06
H3: ✓ Online engagement higher, t(167) = 3.22, p < 0.01, d = 0.49
Primary Hypothesis:
H₀: μexercise = μcontrol (no difference in depression score change)
H₁: μexercise < μcontrol (exercise group shows greater improvement)
Directional Prediction:
"Participants in the exercise intervention will show significantly greater reduction in BDI-II scores compared to waitlist controls at 12 weeks."
3Power Analysis and Sample Size
A Priori Calculations
Expected Effect Size: d = 0.6 (based on meta-analysis)
Alpha Level: 0.05 (one-tailed)
Desired Power: 0.80
Required n: 72 per group
With 20% attrition: 90 per group recruited
Final Analysis
Completed Exercise: n = 76
Completed Control: n = 82
Attrition Rate: 12.2%
Achieved Power: 0.85
4Results and Clinical Significance
Statistical Results:
• Exercise group: M = -12.4 points (SD = 8.2)
• Control group: M = -3.1 points (SD = 7.9)
• Difference: -9.3 points (95% CI: -11.8, -6.8)
• t(156) = -7.32, p < 0.001, d = 1.16
Clinical Significance:
• Large effect size (d > 0.8)
• Clinically meaningful improvement (>5 points BDI-II)
• 68% of exercise group achieved remission vs. 23% control
• Number needed to treat (NNT) = 2.2
💼 Business Research Example
Remote Work Productivity: Organizational Case Study Approach
1Multiple Case Study Design
Cases: Five technology companies (50-500 employees) that transitioned to remote work
Timeframe: Pre-pandemic baseline vs. 12-month remote work period
Sample and Data Collection:
• Online survey: n = 423 e-commerce users
• Interaction with prototype chatbot
• Validated scales for all constructs
• 7-point Likert scales