T4. Sometimes studies with ecologic measures of exposure or outcome report rate differences {called \"absolute rate differences") and rate ratios (called \"incident rate ratios\"). How are researchers able to estimate these values in an ecologic study? Recall that most cross- sectional studies measure the prevalence of a specific outcome, and thus, common measures of association for cross-sectional studies include prevalence difference, prevalence ratio, and prevalence odds ratio. Hint: Think back to definitions of risks and rates compared to prevalence. What would be different about a risk or rate outcome? What is it about that outcome that is so unique and/or how many times can you \"get" the outcome? T5. Winkler et al 2020 describes how our understanding of gun violence in the US has been limited by a ban on NIH funded firearm research, and that there are provisions for CDC 8: NIH funding signed into law in the 2020 US federal budget. The SantaelIa-Tenorio et al 2016 reading for this case study describes an analysis of global research on firearms across 110 countries. What are your thoughts on how these limitations in the US impacted public health knowledge in the eld of firearm injuries and mortality? Do you think this limitation on firearm outcome research is justied? When is it appropriate to set limitations on public health research? What can researchers do to move forward, in light of these restrictions