Parental choice allows some parents to avoid paying local school taxes

The "third variable" issue refers to

a. the possibility that two variables are correlated because both are caused by a third variable. b. the ambiguity introduced when doing more complex research with more than two variables. c. not considering "age" as a variable when doing developmental research. d. the influence of the IV in quantitative experimental research.

Which of the following statements is true of voting requirements for voters in theUnited States?

A. All voters should be twenty-one years of age. B. Voters should be citizens of the United States. C. Voters should abide by a residency requirement of at least sixty days. D. Noncitizens need to take the president's permission to cast their vote. E. To be exempted from voting, a voter needs to produce a medical certificate.