Quantile Regression
Quantile Regression is one of the statistical analyses applied automatically in MerQur. This page illustrates — on a Education Sciences sample dataset — how the analysis is run, what the MerQur output looks like, and how the result is reported in APA 7 format.
🎯 What is it for?
Quantile Regression automatically applies in the background all the assumption checks required for the relevant data type (normality, homogeneity of variance, etc.) and presents the results with a clear table + chart. Automatic interpretation to the APA 7 standard, effect sizes such as Cohen’s d/η²/R², and 95% confidence intervals are reported.
📌 When is it used?
- Statistical analysis of measurements in the Education Sciences domain
- To produce APA 7-compatible result tables for academic publications
- Hypothesis testing and decision-making processes
- Undergraduate / master’s / PhD theses after the appropriate method has been selected
📐 Assumptions
- Appropriate scale — Variables must be at the measurement level required by the analysis (nominal/ordinal/interval/ratio)
- Independent observations — Observations must come from individuals independent of one another
- Sufficient sample size — The minimum n requirement for the analysis must be met
- Outlier check — Outliers must be detected and evaluated
If assumptions are violated, MerQur automatically suggests a non-parametric or robust alternative.
🛠 How to do it in MerQur
Load the data. Select the sample file from File → Open. MerQur auto-detects column types.
Select the analysis. From the left side select Quantile Regression.
Panel assignments (form fields in the program):
- Target Column:
GPA - predictors:
['ogrenci_id', 'calisma_saat'] - quantiles:
[0.25, 0.5, 0.75]
Optional settings. Effect size ✓ · 95% confidence interval ✓ · Assumption checks (automatic).
▶ Run — click the button. Results are produced automatically as a table + chart.
📄 Export to Word. APA 7-formatted report with italic statistical symbols.
📊 Sample Dataset — Education Sciences
ℹ Note: The scenario, MerQur output and interpretation below were produced by actually running the real example dataset in MerQur. Numeric results on your own data will differ; the goal is to show how the analysis is set up and interpreted end-to-end.
🎬 Example File
This analysis is demonstrated on the following example dataset for Education Sciences:
Egitim_Bilimleri/59_quantile_GPA.xlsx
🎬 Scenario
Here we want to know how study_hour and motivation relate to GPA across 200 students, but not just at the average. We suspect these predictors matter differently for struggling students versus high achievers. Quantile regression is the right approach because instead of modeling only the conditional mean, it estimates the effect of study_hour and motivation at different quantiles of the GPA distribution, revealing whether, say, studying more helps low-GPA students more than it helps those already near the top.
⚙️ Variable Selection
- Dependent variable: GPA
- Predictors: study_hour
- Predictors: motivation
Data Preview (First 5 Rows)
| student_id | study_hour | motivation | GPA |
|---|---|---|---|
| 1.0 | 28.8 | 2.34 | 4.0 |
| 2.0 | 15.7 | 4.9 | 3.62 |
| 3.0 | 15.0 | 4.04 | 2.84 |
| 4.0 | 23.1 | 2.76 | 4.0 |
| 5.0 | 16.5 | 3.93 | 3.56 |
n = 200 · Columns: student_id, study_hour, motivation, GPA
📈 MerQur Output
💬 Interpretation
Ordinary regression models only the mean; but study’s effect on GPA may differ for low- and high-achieving students. Quantile regression models the lower (q=0.10, low GPA), middle (q=0.50) and upper (q=0.90, high GPA) quantiles separately. A changing slope across quantiles answers “does study help every student equally” — for instance study may help low achievers more. In education, when the different parts of the distribution (weakest/ strongest students) matter rather than the average, quantile regression reveals what mean-based models miss.
⚠ Common Mistakes
- Misidentifying the data type (e.g., loading a categorical variable as numeric)
- Skipping assumption checks and going straight to the p-value
- Failing to report effect size — APA 7 requires both p and effect size
- Failing to apply a Type I error correction (Bonferroni/Tukey) in multiple comparisons
- Not switching to a non-parametric alternative when n is insufficient
📹 Video Walkthrough
Watch the video below for an end-to-end walkthrough of this analysis on a Education Sciences file.
▶ Quantile Regression — video walkthrough
This section is part of the İleri Düzey I — Gelişmiş Regresyon Modelleri video (8 analyses in one video). The link below jumps straight to 5:33, where this analysis begins. Narration is in Turkish.
🧪 Natural Sciences & Mathematics · 🏛 Architecture, Planning & Design · ⚙ Engineering · 🏥 Health Sciences · 📊 Social, Humanities & Admin Sciences · 🏃 Sport Sciences · 🌾 Agriculture, Forestry & Aquatic
📚 If You Used This Analysis, Cite MerQur
If you performed this analysis using MerQur in a scientific study, please use the citation below as part of your academic citation obligations (APA 7):
Örücü, Ö. K. (2026). MerQur: Integrated Academic Data Analysis & Reporting Platform [Computer software] (Version 1.0.0). https://doi.org/10.53463/merqur.2026001
For BibTeX, RIS, EndNote and the English citation form: all citation formats →
- American Psychological Association. (2020). Publication manual of the American Psychological Association (7th ed.).
- Field, A. (2018). Discovering statistics using IBM SPSS Statistics (5th ed.). Sage.
- Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Lawrence Erlbaum.