S&P 500 - 1998

The following graph plots the year-to-date performance of the index for 1998 compared to the probability calculated by a random walk model.

Initial Value: 970.43 Hist. Volatility: 0.97% Annual Drift: 7% Final Value: 1229.23 Percentile: 85%
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 1998 (what's this?).