An analyst has attempted to optimise a chromatographic process by alteration of the operating conditions. Retention times (min) were determined in replicate, the chromatographic data obtained are given in Table 1. Use appropriate statistical tests to determine whether the retention times obtained for run 2 are statistically higher than those obtained for run 1. Use the 95 % confidence level. Table 1: Chromatographic Data, retention times /min Run 1 9.80 9.50 8.80 9.50 11.1 11.0 Run 2 11.0 10.8 11.1 11.2 10.0