Filed under: Finance
Stochastic volatility models are used in mathematical finance to describe the evolution of asset returns, which typically exhibit changing variances over time.
The dataset is previously analyzed by Harvey et al. (1994), and later by several other authors. The data consist of a time series of daily poundollar exchange rates {zt} from the period 0181 to 285. The series of interest are the daily mean-corrected returns {yt}, given by the transformation
The stochastic volatility model allows the variance of yt to vary smoothly with time. This is achieved by assuming that ,
where
Here, the smoothly varying component xt is assumed to be an autoregression.