Exam 6: Research Validity

A school district decided to try a new computerized testing system. Two schools were selected for the trial based on the students being similar at the beginning of the school year. Students at one school were given the paper-and-pencil version of the test while the students at another school received the computerized test version. The results indicated that the students performed better on the computerized version. However, someone pointed out that on the day of the test there was a fire drill at the school using the paper-and-pencil test. This fire drill confound would be described as

Dr. Kenji wants to determine whether his new phonics program helps children's reading comprehension. He gives a fifth grade class the program and also studies a second grade class that does not go through the program. He finds that the fifth graders read with better comprehension. Identify the confounding variable in this research design.

Jacques surveys fellow students to rate their preferences for various courses on campus. He finds that the sciences are least popular whereas the humanities are most popular. However, he neglects the fact that he performed his survey right after midterm grades were announced. His friend Ghislaine follows up by doing the same survey at the beginning of the following semester and gets very different results. This may be an issue of

Which of the following could be used to eliminate the confounding influence of extraneous variables?

Whether experimental research is conducted in the laboratory, a doctor's office, or at the mall is considered the

Dr. Prentice, principal of an elementary school, instructs her teachers to employ a new aggression-reduction program with the second graders, and to keep using it on that group of students for the next three years. She finds that relative to the start of the program, aggression in that group of students is down 35%. This example illustrates the possibility of________ as a plausible rival hypothesis.

Dr. Dunn is conducting some research involving a new math learning program. To test the effectiveness of the new math program, he selects two sections of his high school math classes to participant in his study. His 1st period 9th grade math class will be the experimental group and his 4th period 11th grade math class will be the control group. Which of the following confounding variable threats is possible in this example?

In general, the accessible population is

Some experiments require observers to take many measures of the dependent variable over time and across participants. If they become better observers of the dependent variable during the course of the study, it produces a confound referred to as

External validity is the extent to which the results of a particular experiment can be generalized to the

Which of the following is NOT true regarding a testing confounding variable?

An experiment was designed to test the effects of rehearsal on memory. In order to hold the extraneous variable "time of day" constant, the experimenter decides to run two groups simultaneously. The rehearsal group is given the instructions live and the other non-rehearsal group sees the same instructions in the next room via closed-circuit television. Live-versus- television is

Janice is taking the SAT to meet an entrance requirement for a college. On her first attempt she scores way below average. She decides to review and then take the test again to see if she can improve her score. She then scored higher the second time she took the test. This example illustrates the possibility of ________ as a plausible rival hypothesis.

One reason it is difficult to conduct long-term studies of the same group of participants is that physical and psychological changes in the participants over time can become confounded with the independent variables) of the experiment. Researchers refer to this as the problem of

Which of the following is an example of the phenomenon of "demand characteristics" acting in an experiment?

Selection bias can be a potential threat to internal validity when subjects are assigned to groups

Dr. Gomez completed her study investigating the effect of stress on consumption of carbohydrates and, based on her analysis of the data, concluded that increasing a person's stress level leads to an increase consumption of carbohydrates. If this inference is correct, the study has achieved

Dr. John, in his study investigating the effect of stress on consumption of carbohydrates, found that stress increased the consumption of carbohydrates. However, he also found that stress increased the desire to consume carbohydrates, the amount of time a person thought about carbohydrates, and the amount of time a person thought about eating. Because stress had the same affect on these other measures that were related to consumption of carbohydrates, the study had

Why is it important for experiments to be externally valid?

A ______variable is one that is not controlled by the experimenter; if this variable has a differential impact on the different groups in the study then it is called a_____ variable.