An epidemiological study involved the comparison of per capita annual income and annual rate of teenage pregnancy in Massachusetts counties in 2012. What type of study is this? a. Case report
b. Case series
c. Ecological study
d. Cross-sectional study

According to the 2008 u. s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of florida was approximately two times the population of california. b. the population of florida was approximately twenty times the population of california. c. the population of california was approximately twenty times the population of florida. d. the population of california was approximately two times the population of florida.

Christina can paint 420 square feet in 105 minutes. which unit rate describes the scenario?

Which pair of numbers is relatively prime? a. 105 and 128 b. 130 and 273 c. 205 and 350 d. 273 and 333