Q: At a chess club, the normal age is 16 years. A sample of 200 chess players is tested with the following results: x=16.15 years and s = 0.20 years. I am trying to find out how to calculate interval with 95% confidence, that the interval contains the actual mean? I am using this T Table for reference. I will do this on my own but can someone present some pointers and advice how to proceed?