121 A researcher investigating the effect of peer tutoring on reading skills studies two groups of children in remedial reading classes. One group receives peer tutoring three times a week for three months, the other group does not. At the end of the three months, the two groups are tested in reading skills. What is the independent variable in this experiment? a. peer tutoring versus no tutoring b. reading skills level at the beginning of the experiment c. reading skills level at the end of the experiment d. reading skills test itself 122. A researcher investigating the effect of peer tutoring on reading skills studies two groups of children in remedial reading classes. One group receives peer tutoring three times a week for three months, the other group does not. At the end of the three months, the two groups are tested in reading skills. What is the dependent variable in this experiment? a. peer tutoring versus no tutoring b. reading skills level at the beginning of the experiment c. reading skills level at the end of the experiment d. the number of children in each group 123. In an experiment testing the effects of a drug on behavior, whether or not a subject receives a drug represents the: a. dependent variable b. independent variable c. control variable d. random variable 124. Which of the following statements best describes the role of a dependent variable? a. It is the variable that the researchers manipulate. b. It is the variable that the researchers measure. c. It is the variable also known as the treatment. d. It is a type of variable used in laboratory research, but not applied research. 125. In an experiment, the variable that the researcher manipulates is called the: a. dependent variable b. independent variable c. controlled variable d. uncontrolled variables 126. A researcher studies how the scores children receive on a spelling test are affected by the amount of sugar they consumed for breakfast. She identifies a group of children and feeds half of them a high-sugar breakfast and feeds the other half a low-sugar breakfast. She gives them the spelling test three hours later. In this study, what is the independent variable? a. the number of words the children can spell correctly on the spelling test b. the number of children tested in the study c. amount of sugar eaten for breakfast d. the difficulty of the words on the spelling test 127. Suppose that Dr. Jones reads about a new study with an interesting result. She decides to repeat the study in her own lab to see if she gets the same result. In this case, Dr. Jones’s study would best be considered a(n): a. validation study b. correlational study c. replication d. independent study 128. Suppose you collect data about child abuse and find that mothers who have their first child before age 18 are more likely to be abusive than mothers who are older. However, you also note that young mothers are also more likely to be poor and have less access to prenatal care. Therefore, you cannot draw conclusions about maternal age and child abuse. The reason you cannot draw this conclusion is because your study involved: a. a sequential-cohort design b. a nonrandom sample c. a nonrepresentative sample d. confounding 129. Which of the following methods of assigning participants to groups in an experiment is the best example of random sampling? a. putting the girls in one group and the boys in another b. making sure that children are able to select the group to which they want to belong c. putting all children’s names in a hat and drawing names to form the groups, even if this results in having unequal numbers of boys and girls in the groups d. having the teacher assign children to groups in order to best separate friends from each other 130. A screening committee rejected a research proposal to study frustration in children because the method involved exposing 5-year-olds to repeated failure on a series of highly difficult tasks. The committee’s decision to reject this study reflected their concern about which ethical principle? a. informed consent b. privacy c. beneficial treatments d. protection from harm