Summary

• Adds mean and standard deviation calculations to delay distribution sessions
• NEW: Creates summarise_lognormal() package function to eliminate code duplication
• Fixes mathematical formula for lognormal standard deviation from the issue
• Includes tidybayes library dependency for both sessions

Changes Made

• NEW: Added summarise_lognormal() function to nfidd R package with proper documentation
• delay-distributions.qmd: Uses new function for mean/sd summary with contextual explanation
• biases-in-delay-distributions.qmd: Uses new function for mean/sd summaries after naive, censored, and truncated model results
• Added tidybayes library to both sessions for spread_draws function
• Corrected the standard deviation formula: sd = exp(meanlog + 0.5 * sdlog^2) * sqrt(exp(sdlog^2) - 1)
• Updated R package NAMESPACE and documentation

Benefits of Package Function Approach

• DRY Principle: Eliminates code duplication across sessions
• Maintainability: Single location for formula updates
• Reusability: Other users can benefit from this utility function
• Cleaner Sessions: Focus on concepts rather than implementation details
• Consistency: Same calculation everywhere

Testing Performed

• Both sessions render successfully with quarto render
• Mathematical formulas verified against lognormal distribution properties
• Code executes without errors and produces expected summary outputs
• New function documented and exported correctly

Note

⚠️ TODO: Double-check lognormal formula for accuracy (flagged for review)

Link to Issue

Closes #293

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