Instruction
1. Define the term “time series” and construct an example graph that you might use in teaching the concept to another student. What variable is on the horizontal axis of your graph? What variable is on the vertical axis in your example? What aspect of the data is most important in such a study, in contrast to traditional statistics? What aspect is less important?
2. How does a time series design change our way of looking for evidence of an "effect" or "no effect" of a treatment or other interruption event? Give a public policy example in which different opinions exist about the effectiveness of a change in the law, or a change in government, or an “interruption” in general.
3. Why would you warn a public official not to simply average data over several years in evaluating the impact of a law?
4. Select some archived time series data from the internet. Browse it and understand what it is about. Construct a graph of a portion of this data, focusing on an aspect of it that interests you. Write a paragraph about this exploratory exercise.
5. Do the same thing with an archived data set that is not a time series.