iShares S&P/Citigroup 1-3 Year Int Trsry - 2011  (Inactive Symbol)

The following graph plots the year-to-date performance of the stock for 2011 compared to the probability calculated by a random walk model.

Initial Value*: $97.7 Hist. Volatility: 0.52% Annual Drift: 7% Final Value*: $94.9 Percentile: 20%
Click on the image for the high resolution version.

The high to date and low to date prices of the stock plotted against a random walk model for 2011 (what's this?).