1. Finch Beak Data. Explain why the finch beak study is considered an observational study.

2. For comparing two population means when the population distributions have the same standard deviation, the standard deviation is sometimes referred to as a nuisance parameter. Explain why it might be considered a nuisance.

3. True or false? If a sample size is large, then the shape of a histogram of the sample will be approximately normal, even if the population distribution is not normal.

4. True or false? If a sample size is large, then the shape of the sampling distribution of the average will be approximately normal, even if the population distribution is not normal.

5. Explain the relative merits of 90% and 99% levels of confidence.

6. What is wrong with the hypothesis that Y 2 - Y 1 is 0?