Hello, I am having a hard time solving this problem: The interval (20.6, 26.2) is a 90% confidence interval. Construct a 95% confidence interval for the same data. Use n=30. Thank you.

Hello, I am having a hard time solving this problem: The interval (20.6, 26.2) is a 90% confidence interval. Construct a 95% confidence interval for the same data. Use n=30. Thank you.

Since you are given "n= 30" it sounds like you have a binomial distribution with some probability "p". For such a distribution the mean is np= 30p and the standard deviation is \(\displaystyle \sqrt{np(1-p)}\). Knowing the "90% confidence interval" you should be able to calculate p and then the 95% confidence interval.