Question

If someone gives you a sample mean and a standard deviation, you can find a confidence interval. But what if someone gives you the confidence interval instead and asks you to find the sample mean? How can you do that? Here's an example: a 95% confidence interval for a mean is 9.5 to 12.5. What is the sample mean?

Answer 1

Take the two values, add together, then divide by 2. That value will be the mean.