Goal: Tests whether EUR/USD daily returns behave like a random walk (fair coin) using statistical tests and simulations.
- Asset: EUR/USD exchange rate (Yahoo Finance ticker: EURUSD=X)
- Frequency: Daily closing prices
- Period: January 2010 – January 2025 (~3,900 observations)
- Transformations:
- Returns calculated as daily percentage changes
- Converted to binary sequence: 1 = up day, 0 = down day
 
This preprocessing allows direct comparison with simulated coin flips.
- Bias test (binomial)
- Runs test (Wald-Wolfowitz)
- Longest streak Monte Carlo
- Markov transition probabilities
- Autocorrelation & Ljung-Box
- Hurst exponent (R/S method)
- Shannon entropy
- Permutation test (toy momentum rule)
- No directional bias (49.5% up days, p=0.52)
- Runs and longest streaks consistent with randomness
- No short-term memory (Markov, permutation)
- Volatility clustering in squared returns (p < 1e-70)
- Mild persistence (Hurst ≈ 0.55)
- Entropy ≈ 1.0 bits → near-max unpredictability
- 📑 Research Paper PDF
- 📸 Figures in docs/charts/
- 📂 Notebook
- 🖼️ Summary Slide