Advanced Clinical Trial Randomization Algorithm

Create an Excel-based educational tool that demonstrates stratified randomization for clinical trials using complex Power Query and statistical functions. The solution should: 1) Allow researchers to input patient characteristics, 2) Implement block randomization with variable block sizes, 3) Ensure balanced group allocation, 4) Generate reproducible randomization sequences, 5) Provide visual representations of group distributions. Include detailed documentation explaining the randomization methodology and statistical principles.