can be seen that the mean daily returns are close to zero for all periods. The largest (absolute) mean daily return is negative 9.5 basis points per day, -21.2% per year, for the CSCE series in the second subperiod. The daily standard deviation of the CSCE returns series is slightly, but significantly4 greater than the daily standard deviation of the LIFFE returns series in all periods. The daily volatility of the Pound-Dollar series is much smaller, by a factor more than two measured in standard deviations, than the volatility of both cocoa series in all subperiods. All data series show excess kurtosis in comparison with a normal distribution and show some sign of skewness. The table also shows the maximum consecutive decline of the data series in each period. For example the CSCE cocoa futures continuation series declined with 85.1% in the period May 23, 1984 until February 20, 1997. The Pound lost 47.5% of its value against the Dollar in the period February 27, 1985 until September 2, 1992. Hence, if objective trend-following trading techniques can avoid being in the market during such periods of great depreciation, large profits can be made.
Table 2.2 shows the estimated autocorrelation functions, up to order 20, for all data series over all periods. Typically autocorrelations are small with only few lags being significant.5 The CSCE series shows little autocorrelation. Only for the first subperiod the second order autocorrelation is significant at a 5% significance level. The LIFFE series shows some signs of low order autocorrelation, significant at the 10% level, in the first two subperiods. The Pound-Dollar series has a significant first order autocorrelation at a 1% significance level, mainly in the first two subperiods.