1. Take a look at this link ( https://drive.google.com/file/d/1Ff6Mm1iAMP-O2g5tXc82oG7MjzZ-nSdk/view?usp=sharing ) and explain in detail about your answers to the following items:

(a) Develop a causal theory about the relationship between an independent variable (X) and a dependent variable (Y) from this data set. Is it the credible causal mechanism that connects X to Y? Explain your answer. (b) Could Y cause X? Explain your answer. (c) What other variables (Z) would you like to control for in your tests of this theory?

2. Read this link ( https://drive.google.com/file/d/1L5B4SycVOREwyY6-PKhxJYJX8b2PPKmk/view?usp=sharing ). Explain why the correlation may not be causation, in this case.

3. For each of the following articles, identify the spatial unit(s) and time unit(s). For each, say whether the study was an experiment, a cross-sectional observational study, or a time-series observational study. (there are three links for this and i need three in-depth answers, make sure to fully answer the question without leaving anything)

https://drive.google.com/file/d/1nISHlTLV3vCUYyvAqvIUDI3Of0ve_WoA/view?usp=sharing

https://drive.google.com/file/d/1nrmRetp1AR6xnGjIvZmsie3Xwsd4TUhx/view?usp=sharing

https://drive.google.com/file/d/1CdF17LYHI14HTMdOrdlIOaoKywdtDvIT/view?usp=sharing

4. Table 4.2 presents data ( https://drive.google.com/file/d/1hyFuw6pXCLsTq6MVtP9bKWk3QX-6Ejjw/view?usp=sharing ) for a test of a theory by use of a time-series observational study. If this same theory were tested by use of a cross-sectional observational study, what would the data table look like?

5. Compare the two designs for testing the preceding theory. Across the two forms of observational studies, what are the Z variables for which you want to control?