Marnie works at a supermarket. Marnie notices that children in the supermarket often misbehave while shopping with a caregiver, and she decides to conduct an experiment to determine whether supermarket personnel can do anything to discourage the behavior. She recruits friends to serve as data collectors but makes a point not to share her hypothesis with them. One Friday from 12:00 P. M. to 2:00 P. M., one of her research team members offers a small piece of candy to every fifth child who comes through the door with a caregiver. The child must be small enough to be placed in a shopping cart. Another team member follows and monitors the child for the occurrence of misbehaving (operationally defined as instances of screaming, loud crying, or grabbing inappropriately at merchandise or people). On the following Sunday from 12:00 P. M. to 2:00 P. M. Marnie dispatches a research team member to follow every fifth child in the targeted age range (young enough to fit in a shopping cart), but they were not to offer candy or intervene in any way. She will compare the degree to which children act out and disturb other shoppers in the two conditions. Her belief is that by distracting the child with sugar, the child will act out less. When she tallies the number of misbehaviors, she is surprised to discover that the children who received candy actually had more instances of misbehavior than those who did not.

RESULTS OF THE CANDY CONDITION

Child 1 2 3 4 5 6 7 8 9 10
Number of Misbehaviors 3 2 3 8 3 4 4 3 1 0

RESULTS OF THE NO-CANDY CONDITION

Child 1 2 3 4 5 6 7 8 9 10
Number of Misbehaviors 0 0 1 1 4 2 2 0 1 1

Identify the independent variable.
Describe Marnie’s strategy for subject assignment.