1-Can you give a general rule as to what happens with confidence intervals as a function of sample sizes and confidence levels? What are the trade-offs?
2-Take a sample of something in your work environment, something simple, and calculate a confidence interval.
Some possible samples: the average number of people in your unit for the last few weeks; the average number of people in cars you pass on the freeway (be careful - maybe do this when carpooling); the average length of a phone call; the proportion of men vs women that you see in a day.
Does the confidence interval surprise you? Interpret it.