Discussions:
1. Suppose that we will randomly select a sample of four measurements from a larger population of measurements. The sampling distribution of the sample mean is the probability distribution of a population. In your own words, describe the units in this population.
2. Explain what is meant by a margin of error for a confidence interval.
3. Why do we need to take a preliminary sample when determining the size of the sample needed to make the margin of error of a confidence interval equal to E?