Exam 8: Experiments

A new program designed to boost math scores based on different teaching strategies is enacted in a classroom.Neither the teacher,nor the students know specifically that they are the experimental group in this research project.This would be an example of

Professor Rose was asked to design an experiment to test whether obese people would lose weight on a new diet plan.Professor Rose was not a methodologist.Rose asked for your help.You immediately told Rose that the selected design would have to be sensitive to the issues of statistical regression,diffusion or imitation of treatment,compensatory rivalry,and demoralization.Rose said,"I don't understand." Explain these issues to Rose.Suggest and explain a design that would control for these problems.

A friend of yours,a senior,took the Graduate Record Exam in September and scored in the 99th percentile.In February,your friend took the same exam over again.This time your friend scored in the 84th percentile.As a research methods student,you told your friend that his/her lowered score was most likely due to

Conducting research on the world wide web helps to insure representative samples

The classical experimental design controls for an interaction between the testing and the stimulus.

An experiment examines the effect of the

Joelle was conducting a six-month experiment in which she was interviewing members of the community to determine if a new police-community outreach program increased positive perception of police officers amongst the community.Four months into the experiment,a scandal regarding police brutality hit the news in a neighboring city,which had an effect upon this community's perception of police.Which source of internal invalidity does this example reflect?

Questions about the generalizability of findings are more likely to be raised about explanatory studies using college students than on descriptive studies using college students.

Manuello did an experiment on workers in an insurance company to examine the effect of a new computer system on workers' attitudes and productivity.He had no control group.He noticed that as he simplified the computer system,worker productivity and positive attitude went up.He then complicated the computer system and monitored the workers closely,only to discover that their productivity and positive attitude again increased.What was probably at work?

The easiest of the true experimental designs to conduct is the

A researcher was conducting an experiment on a new method to reduce fear of flying and did not use a control group.During this experiment,a high-profile plane crash was reported in the media.What threat to internal validity is this?

The effectiveness of randomization in experimentation is affected by the number of subjects involved.

Latona did an experiment at a military barracks over the space of a few months to examine the effect of group size on group morale.He randomly assigned soldiers to the experimental and control groups and did a pretest and posttest.Midway through the experiment,some of the soldiers were re-assigned to different stations across the U.S.causing the sample size to drop.Which source of internal invalidity does this example reflect?

The difference between the experimental and control groups should be that the

The double-blind experiment is one in which

Preexperimental designs do not have control groups.

Bill conducted an experiment to determine the effectiveness of a drug prevention program in high school.This group was compared to students at another high school that did not take part in the program.The students were given an exam before and after taking part in the program.As the students completed the posttest,many realized that it was the same test they took before the program and put in random answers,as teenagers would.This is a case of what invalidity problem?

An instrumentation effect occurs when

Misty did an experiment in which half of her subjects were told that they had extrasensory perception and half were not.In reality,there was no difference.Interestingly,at the end of the three-month experiment,those subjects who were told that they had extrasensory perception actually outscored the control group on the ability to accurately describe video scenes with the sound turned off.This example reflects

The use of an experimental group allows the researcher to detect any effects of the experiment itself.