A friend of your's gets a new job working in an ornithology lab (studying birds). They are given a large dataset on clutch sizes (number of baby birds) for a specific breed of sparrow, and taught how to use excel to calculate a confidence interval. They use excel calculate a confidence interval and get the values [2.8, 3.3] when using the "95%" setting.

Unfortunately your friend doesn't know what that actually means, and they are nervous about asking the lab director and looking ill prepared for their job. Lucky, their friend just took STAT220, so they turn to you for help.

They ask you to explain the following:

1. What is a confidence interval, in general?
2. What do the specific values of (2.8, 3.3) mean in the context of this dataset?
3. What does the "95%" setting change?