Tell whether each of the following is a paired, two-sample, or several-sample design, and whether each would involve t or F as the standardized statistic.

a. Gather data to see if Verbal SAT scores differ significantly depending on whether a student's first language learned is English, another language, or English and another language both spoken since birth.

b. Gather data to see if disabled students' Math SAT scores are significantly lower than their Verbal scores.

c. Gather data to see if disabled students' Math SAT scores are significantly lower than those of nondisabled students.