The U.S. Supreme Court erased many barriers to African American participation, striking down state poll tax laws in 1966

The major difference between the hypothesis-testing procedures in factorial versus single-variable designs is that

A) single-variable designs, although less complicated in terms of design, are more difficult to interpret. B) there are more dependent variables in the factorial design. C) the reasoning is very different in each type of design. D) there is more chance for confounding to occur in factorial designs.

Although there was some dissent, the majority at the Philadelphia Convention agreed that

A) the central government was too strong. B) the central government needed to be strengthened. C) slavery should be slowly phased out of the United States. D) state governments were too strong. E) both C and D