Vanguard Long Term Corporate Bond ETF - 2013  (Inactive Symbol)

The following graph plots the year-to-date performance of the stock for 2013 compared to the probability calculated by a random walk model.

Initial Value*: $78.1 Hist. Volatility: 0.43% Annual Drift: 7% Final Value*: $74.1 Percentile: 9%
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 2013 (what's this?).