In developing a confidence interval estimate for the difference between two population means when the population variances are known, an increase in the size of the samples will result in:
A) a wider confidence interval.
B) a narrower confidence interval.
C) a smaller z critical value.
D) the same confidence interval.

Question

Quizplus · Accepted Answer

Increasing the sample size will result in a decrease in the standard error and a narrower confidence interval. This is because as the sample size increases, the estimate of the population mean becomes more precise and the standard error decreases. Therefore, a larger sample size results in a more accurate estimate of the population mean, hence a narrower confidence interval.

In Developing a Confidence Interval Estimate for the Difference Between