# Confidence interval and sample size calculation

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 (- 0.1, 1.5). 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 smaller margin of error for the difference between two sample means?

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Basic concepts. For each of the following, answer the question and give a short explanation of your reasoning.

a. A 95% confidence interval for ...

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Step by step method for computing confidence interval and sample size is given in the answer.