Question

Question 1: if you were to calculate a confidence interval using a confidence level of 0.9 and then calculated a second confidence interval using the same data but changed the confidence level to 0.95, would the interval be more narrow or wider?

Answer 1

The confidence interval would be wider so that you can be more confident that the parameter you're measuring (eg: population mean mu) is inside the confidence interval. 

It's like saying "the treasure is somewhere in the country" which is fairly vague but could be true. To be more confident, you can update it to "the treasure is somewhere on the continent". It's even more vague but it increases the chances of being correct.