Belsky, Weinraub, Owen, and Kelly (2001) reported on the effects of preschool childcare on the development of young children. One result suggests that children who spend more time away from their mothers are more likely to show behavioral problems in kindergarten. Suppose that a kindergarten teacher is asked rank order the degree of disruptive behavior for the n = 20 children in the class.
a. Researchers then separate the students into two groups: children with a history of preschool and children with little or no experience in preschool. The researchers plan to compare the ranks for the two groups.
b. The researchers interview each child's parents to determine how much time the child spent in preschool. The children are then ranked according to the amount of preschool experience. The researchers plan to use the data to determine whether there is a relationship between preschool experience and disruptive behavior.