Question

To compare two population means, two independent sample data are used to construct a confidence interval and perform a two-sided significance test to obtain a P-value. Explain what you could learn from a confidence interval comparing the means that you are not able to learn from a Pvalue.

Answer 1

P value from the hypothesis test gives only the probability value, which is then used to reject or accept the null hypothesis. When we talk about confidence interval, the confidence interval for two population means using the data from two independent samples gives us information about the hypothesis testing and at the same time it gives us the range of values for the mean difference between the two populations.

So, the confidence interval helps in testing the hypothesis and at the same time, it provides the population mean difference with a specified level of confidence. If the null value is included in the confidence interval, then we fail to reject the null hypothesis, but if the null value is not included in the confidence interval, then we reject the null hypothesis.