Improved correlation checks and reduced false positives in missing patterns

Improvements

• Refined correlation checks in calculate_correlations
  • Fixed type inference errors by iterating over analyzer.column_types instead of analyzer.df
  • Updated mixed-variable thresholds to {'warning': 0.5, 'critical': 0.8} for consistency with Cramer’s V
  • Ensured seamless integration with run_checks
• Reduced over-flagging in missing patterns detection
  • Introduced effect size thresholds:
    • Categorical: Cramer’s V > 0.1
    • Numeric: Cohen’s d > 0.2
  • Tightened p-value threshold to 0.01
  • Increased minimum samples per group to 10
  • Replaced ANOVA (f_oneway) with Mann-Whitney U test for better handling of skewed distributions
  • Added pattern grouping to summarize correlations per missing column (top 3 shown for conciseness)

Fixes

Corrected correlation dictionary iteration (analyzer.column_types)
Prevented spurious warnings by filtering weak associations