4. A medical researcher is interested in the possible role of a particular vaccine in causing autism. She identifies 50 autistic children and matches them with 50 similar age children from the same neighborhoods who were not autistic. She then determines which of the children had been given the vaccine. These are the results:
Group
Vaccine       Autistic    Normal       Total
Yes                   21            15            86
No                     29            35             64
Total                  50            50            100
a. What type of study design was used in this research?
b. Calculate and interpret the relative risk and odds ratio of autism for vaccine recipients v. non-recipients.
c. Which of the two comparative measures is more meaningful in this instance and why?
5. Search online to find the population of all cities and towns in Massachusetts. Make a simple frequency distribution of the first (left-hand) digit of the populations. Include percentages, cumulative frequencies, and cumulative percentages. What pattern do you see in the frequency distribution? Does it look like all digits are equally likely? If not, think about why that might be?