Analysis Overview and Data Quality
Mann-Whitney U Test Configuration
Analysis overview and configuration
mann_whitney_test_20260307_231158
Analysis Overview
This analysis compares ad exposure levels between two treatment groups—an advertisement group (ad) and a public service announcement group (psa)—using a Mann-Whitney U test. The non-parametric approach was selected to avoid assumptions about data distribution, making it appropriate for comparing exposure metrics that may be skewed or non-normally distributed across unequal sample sizes.
The ad group demonstrates significantly higher exposure than the psa group. The U statistic of 7807.5 and mean rank difference (
Analysis Overview
This analysis compares ad exposure levels between two treatment groups—an advertisement group (ad) and a public service announcement group (psa)—using a Mann-Whitney U test. The non-parametric approach was selected to avoid assumptions about data distribution, making it appropriate for comparing exposure metrics that may be skewed or non-normally distributed across unequal sample sizes.
The ad group demonstrates significantly higher exposure than the psa group. The U statistic of 7807.5 and mean rank difference (
Data Quality & Completeness
Data preprocessing and column mapping
Data Preprocessing
This section documents the data preprocessing pipeline for the Mann-Whitney U test comparing ad exposure between treatment groups. Perfect data retention (100%) indicates no rows were removed during cleaning, meaning all 500 observations proceeded to statistical analysis without filtering or exclusion.
The complete data retention reflects a clean dataset requiring no exclusions for missing values, outliers, or data quality issues. This preserves the full sample size advantage for the Mann-Whitney U test, which relies on rank-based comparisons across all observations. The imbalanced group sizes (475 vs. 25) remain intact, which is appropriate for this non-parametric test that doesn’t assume equal variances or normal distributions.
No transformations or filtering were applied, so the analysis operates on raw exposure values. The absence of preprocessing decisions means observed differences in medians (79 vs. 35) and rank distributions reflect genuine group variation rather than artifacts of data cleaning.
Data Preprocessing
This section documents the data preprocessing pipeline for the Mann-Whitney U test comparing ad exposure between treatment groups. Perfect data retention (100%) indicates no rows were removed during cleaning, meaning all 500 observations proceeded to statistical analysis without filtering or exclusion.
The complete data retention reflects a clean dataset requiring no exclusions for missing values, outliers, or data quality issues. This preserves the full sample size advantage for the Mann-Whitney U test, which relies on rank-based comparisons across all observations. The imbalanced group sizes (475 vs. 25) remain intact, which is appropriate for this non-parametric test that doesn’t assume equal variances or normal distributions.
No transformations or filtering were applied, so the analysis operates on raw exposure values. The absence of preprocessing decisions means observed differences in medians (79 vs. 35) and rank distributions reflect genuine group variation rather than artifacts of data cleaning.
Key Findings and Recommendations
Key Findings & Recommendations
| Finding | Value |
|---|---|
| Test Result | Significant (p=0.0079) |
| Effect Size | -0.315 (Medium) |
| Group 1 Median | 79.00 (n=475) |
| Group 2 Median | 35.00 (n=25) |
Bottom Line: Compared ad (n=475) vs psa (n=25) using Mann-Whitney U test. Significant difference found (p=0.0079, effect size r=-0.315).
Key Findings:
• Median ad: 79.00
• Median psa: 35.00
• Effect magnitude: Medium
Recommendation: Groups differ meaningfully - take action based on context
Executive Summary
This analysis compared ad exposure levels between two treatment groups (ad vs. psa) using a non-parametric Mann-Whitney U test. The objective was to determine whether statistically and practically meaningful differences exist in ad exposure between these groups, with results informing campaign strategy decisions.
The ad group received substantially higher exposure than the psa group, and this difference is both statistically significant and practically meaningful. The medium effect size indicates this is not merely a trivial statistical artifact. The analysis successfully achieved its objective: demonstrating a clear, defensible distinction in ad exposure between treatment
Executive Summary
This analysis compared ad exposure levels between two treatment groups (ad vs. psa) using a non-parametric Mann-Whitney U test. The objective was to determine whether statistically and practically meaningful differences exist in ad exposure between these groups, with results informing campaign strategy decisions.
The ad group received substantially higher exposure than the psa group, and this difference is both statistically significant and practically meaningful. The medium effect size indicates this is not merely a trivial statistical artifact. The analysis successfully achieved its objective: demonstrating a clear, defensible distinction in ad exposure between treatment
Mann-Whitney U Test Statistics
U Statistic and P-Value
Mann-Whitney U test statistical results
Test Results
This section presents the statistical test results from a Mann-Whitney U test comparing ad exposure between the treatment (ad) and control (psa) groups. The test determines whether observed differences in ad exposure distributions are statistically significant or due to random variation, directly addressing the analysis objective of comparing exposure between groups.
The Mann-Whitney U test confirms that ad exposure differs significantly between groups. The ad group (median = 79) demonstrates substantially higher exposure than the psa group (median = 35). With a p-value of 0.0079, this difference is unlikely due to chance. The medium effect size (-0.315) indicates this is not merely a statistical artifact but represents a meaningful practical difference in
Test Results
This section presents the statistical test results from a Mann-Whitney U test comparing ad exposure between the treatment (ad) and control (psa) groups. The test determines whether observed differences in ad exposure distributions are statistically significant or due to random variation, directly addressing the analysis objective of comparing exposure between groups.
The Mann-Whitney U test confirms that ad exposure differs significantly between groups. The ad group (median = 79) demonstrates substantially higher exposure than the psa group (median = 35). With a p-value of 0.0079, this difference is unlikely due to chance. The medium effect size (-0.315) indicates this is not merely a statistical artifact but represents a meaningful practical difference in
Distribution of Values by Group
Distribution by Group
Visual comparison of group distributions
Group Comparison
This section visualizes the raw distribution of ad exposure values across the two treatment groups to establish whether observed differences are meaningful. The box plot enables direct comparison of central tendency, spread, and outlier patterns between the ad group (n=475) and psa group (n=25), providing context for the Mann-Whitney U test results.
The ad group demonstrates consistently higher ad exposure values across the distribution, with a median nearly 2.5 times that of the psa group. This visual separation aligns with the Mann-Whitney U test’s statistically significant finding (p=0.008) and supports the medium effect size (r=-0.315). The similar distribution shapes confirm that differences reflect genuine exposure disparities rather than structural artifacts.
The substantial sample size imbalance (475 vs 25
Group Comparison
This section visualizes the raw distribution of ad exposure values across the two treatment groups to establish whether observed differences are meaningful. The box plot enables direct comparison of central tendency, spread, and outlier patterns between the ad group (n=475) and psa group (n=25), providing context for the Mann-Whitney U test results.
The ad group demonstrates consistently higher ad exposure values across the distribution, with a median nearly 2.5 times that of the psa group. This visual separation aligns with the Mann-Whitney U test’s statistically significant finding (p=0.008) and supports the medium effect size (r=-0.315). The similar distribution shapes confirm that differences reflect genuine exposure disparities rather than structural artifacts.
The substantial sample size imbalance (475 vs 25
Rank Analysis Across Groups
Rank Comparison Across Groups
Distribution of ranks across groups
Rank Distribution
This section reveals how the Mann-Whitney test transforms raw ad exposure values into ranks for statistical comparison. By analyzing rank distributions, we can understand whether one group systematically occupies higher or lower positions in the overall exposure hierarchy, independent of actual exposure magnitudes. This rank-based approach is particularly valuable when data contains outliers or skewness.
The ad group’s higher mean rank (254.4 vs. 175.7) directly explains the statistically significant Mann-Whitney result (p=0.008). This 31% rank differential indicates the ad group consistently receives greater ad exposure than the psa group. The rank-based comparison neutralizes the impact of extreme outliers while preserving the ordinal relationship between observations, making this finding robust regardless
Rank Distribution
This section reveals how the Mann-Whitney test transforms raw ad exposure values into ranks for statistical comparison. By analyzing rank distributions, we can understand whether one group systematically occupies higher or lower positions in the overall exposure hierarchy, independent of actual exposure magnitudes. This rank-based approach is particularly valuable when data contains outliers or skewness.
The ad group’s higher mean rank (254.4 vs. 175.7) directly explains the statistically significant Mann-Whitney result (p=0.008). This 31% rank differential indicates the ad group consistently receives greater ad exposure than the psa group. The rank-based comparison neutralizes the impact of extreme outliers while preserving the ordinal relationship between observations, making this finding robust regardless
Practical Significance Assessment
Rank-Biserial Correlation with CI
Effect size and practical significance
Effect Size
This section quantifies the practical magnitude of the difference in ad exposure between treatment groups. While the p-value (0.008) confirms statistical significance, effect size reveals whether this difference is practically meaningful. This bridges the gap between statistical significance and real-world impact for comparing ad versus PSA exposure.
The negative coefficient reflects that the ad group occupies higher ranks (median: 79) compared to the PSA group (median: 35). This medium effect size demonstrates the ad exposure difference is not only statistically significant but also practically substantial. The confidence interval’s width suggests reasonable precision, though the lower bound approaches small-effect territory, indicating some uncertainty in the exact magnitude.
Effect size interpretation depends on domain context; medium effects may be trivial or important depending on
Effect Size
This section quantifies the practical magnitude of the difference in ad exposure between treatment groups. While the p-value (0.008) confirms statistical significance, effect size reveals whether this difference is practically meaningful. This bridges the gap between statistical significance and real-world impact for comparing ad versus PSA exposure.
The negative coefficient reflects that the ad group occupies higher ranks (median: 79) compared to the PSA group (median: 35). This medium effect size demonstrates the ad exposure difference is not only statistically significant but also practically substantial. The confidence interval’s width suggests reasonable precision, though the lower bound approaches small-effect territory, indicating some uncertainty in the exact magnitude.
Effect size interpretation depends on domain context; medium effects may be trivial or important depending on
Group Descriptive Statistics
Group Descriptive Statistics
Descriptive statistics by group
Summary Statistics
This section provides the foundational statistics needed to understand the Mann-Whitney U test comparison between ad and PSA groups. The rank-based metrics (mean rank and sum of ranks) are the core calculations that drive the statistical test, making this table essential for interpreting whether ad exposure differs significantly between treatment groups.
The descriptive statistics reveal a clear central tendency difference: the ad group exhibits both higher median values and higher average ranks, suggesting greater ad exposure overall. The rank sums directly feed into the U statistic calculation; the ad group’s substantially
Summary Statistics
This section provides the foundational statistics needed to understand the Mann-Whitney U test comparison between ad and PSA groups. The rank-based metrics (mean rank and sum of ranks) are the core calculations that drive the statistical test, making this table essential for interpreting whether ad exposure differs significantly between treatment groups.
The descriptive statistics reveal a clear central tendency difference: the ad group exhibits both higher median values and higher average ranks, suggesting greater ad exposure overall. The rank sums directly feed into the U statistic calculation; the ad group’s substantially
Distribution Similarity Check
Shape Similarity Assessment
Distribution shape similarity assessment
Distribution Check
This section validates whether the Mann-Whitney U test is appropriately applied by assessing distribution shape similarity between the ad and psa groups. Since non-parametric tests assume similar distributional shapes, confirming this assumption justifies comparing medians directly rather than relying on rank comparisons alone.
The shape ratios (0.098 vs. 0.282) are sufficiently close to confirm distributional similarity, validating the Mann-Whitney U test’s core assumption. This means the observed median difference (ad: 79 vs. psa: 35) reflects a genuine difference in ad exposure between groups rather than an artifact of different distribution shapes. The similar shapes support the statistical significance finding (p = 0.008) as a reliable comparison of central tendency.
This assessment assumes I
Distribution Check
This section validates whether the Mann-Whitney U test is appropriately applied by assessing distribution shape similarity between the ad and psa groups. Since non-parametric tests assume similar distributional shapes, confirming this assumption justifies comparing medians directly rather than relying on rank comparisons alone.
The shape ratios (0.098 vs. 0.282) are sufficiently close to confirm distributional similarity, validating the Mann-Whitney U test’s core assumption. This means the observed median difference (ad: 79 vs. psa: 35) reflects a genuine difference in ad exposure between groups rather than an artifact of different distribution shapes. The similar shapes support the statistical significance finding (p = 0.008) as a reliable comparison of central tendency.
This assessment assumes I
Statistical and Business Interpretation
Statistical and Business Interpretation
Statistical and business interpretation
| Component | Result |
|---|---|
| Statistical Significance | Significant (p=0.0079) |
| Effect Size | -0.315 (Medium) |
| Group 1 | Median=79.00, n=475 |
| Group 2 | Median=35.00, n=25 |
Interpretation
This section synthesizes the Mann-Whitney U test results to determine whether ad exposure differs meaningfully between treatment groups. It validates whether the observed difference in median exposure (79 vs. 35) represents a genuine effect or random variation, directly addressing the core analysis objective.
The analysis reveals that the ad group received meaningfully higher exposure than the PSA group. The p-value confirms this difference is statistically reliable, while the medium effect size indicates the practical magnitude is substantial. The similar distribution shapes (shape_similar = TRUE) validate the Mann-Whitney U test’s appropriateness for this comparison.
The severe sample size
Interpretation
This section synthesizes the Mann-Whitney U test results to determine whether ad exposure differs meaningfully between treatment groups. It validates whether the observed difference in median exposure (79 vs. 35) represents a genuine effect or random variation, directly addressing the core analysis objective.
The analysis reveals that the ad group received meaningfully higher exposure than the PSA group. The p-value confirms this difference is statistically reliable, while the medium effect size indicates the practical magnitude is substantial. The similar distribution shapes (shape_similar = TRUE) validate the Mann-Whitney U test’s appropriateness for this comparison.
The severe sample size