A paired difference experiment compared two methods (x1 and x2) and found a mean difference (d) of 3.5 with a standard deviation (sd) of 3.5. To test the null hypothesis that the true difference is 0 against the alternative that x1 is less than x2, the z-statistic must be less than -1.282 for a one-tailed test with α=0.1. Since the calculated z-statistic is not in the rejection region, there is not enough evidence to reject the null hypothesis.