Basic concepts. For each of the following, answer the question and give a short explanation of your reasoning.
(a) A 95% confidence interval for the difference between two means is reported as (0.8, 2.3). What can you conclude about the results of a significance test of the null hypothesis that the population means are equal versus the two-sided alternative?
(b) Will larger samples generally give a larger or a smaller margin of error for the difference between two sample means?