Question 1

Two types of psychotherapy are compared for treating depression. A random half of the subjects receive each of the treatments. What type of design does this study represent?

Accepted Answer

This study represents a single-factor between-subjects design where two groups are randomly assigned to different treatments and then compared on the outcome measure of depression. The study does not involve within-subjects comparisons or pretest-posttest measurements, and there is a control group (the other treatment group) in place. There is no indication of a posttest-only design as there is no mention of a control group that did not receive either treatment.

Question 2

A researcher would like to know whether his new dog training program is effective. He tests a group of dogs before they start the program, and then again afterwards. What research design has he used?

Accepted Answer

This is a one-group pretest-posttest design because the researcher is measuring the same group of dogs before and after the intervention without comparing them to a control group.

Question 3

A psychology professor wants to test the effectiveness of providing students in his introductory experimental psychology class with an outline of his weekly lecture notes. He forms two groups within his class, each containing 24 students. The experimental group receives an outline of the professor's weekly lectures, and the control group receives no outline. Grades at the end of the course are compared between the two groups. On the basis of this description, discuss what flaw is most evident in the design of the experiment. Identify and design and discuss an alternative procedure that might eliminate the flaws.

Accepted Answer

The answer of A psychology professor wants to test the...

Question 4

A researcher plans a study to test the effectiveness of the discussion method in an introductory research methods course at the college level. One instructor will use the discussion method in her class several times during the semester. Another instructor will teach the same content, but without using the discussion method. The researcher will collect the following data: student scores on mid-term and final exams and on a scale measuring attitudes toward instruction. Discuss at least three recommendations that you can provide to improve this experimental design.

Accepted Answer

The answer of A researcher plans a study to test...

Question 5

O X O O represents the

Accepted Answer

The answer of O X O O represents the
...

Question 6

The experiment by Braun, Ellis, and Loftus 2002) on the effect of a Disney advertisement on memory for visiting a theme park was done between subjects because

Accepted Answer

The experiment was done between subjects because if the participants experienced both conditions of the study, they would no longer be naïve about the independent variable, which could lead to demand characteristics or experimenter bias.

Question 7

O X O represents the

Accepted Answer

The "O X O" notation represents a research design where "O" stands for an observation or measurement (pretest and posttest) and "X" represents an intervention or treatment. This sequence indicates a one-group pretest-posttest design, where a single group is measured before and after an intervention.

Question 8

To determine the effect of counseling on the self-esteem of divorced women, a researcher measures the self-esteem of a group of women before and after they have received counseling and compares the before and after measurements. What type of design does this study represent?

Accepted Answer

This study represents a one-group pretest-posttest design since there is only one group of women being measured both before and after counseling.

Question 9

Consider the posttest-only design with nonequivalent control groups. Can you think of an experimental situation in which this design might be necessary? How could you potentially strengthen the experimental design?

Accepted Answer

The answer of Consider the posttest-only design with nonequivalent control...

Question 10

You decide that you want to see whether a popular motivational program "Optimize Your Life!" actually works. You survey the participants after they have taken part in the study. This experimental design is called a

Accepted Answer

This design is called a "One-group posttest-only design" because it involves surveying participants only after they have taken part in the program, without a pretest or a control group for comparison.

Question 11

R O X O O represents the

Accepted Answer

R O X O O represents the pretest-posttest control group design, where "R" stands for random assignment, "O" represents observation or measurement, and "X" is the intervention or treatment. This design involves measuring both the experimental and control groups before and after the intervention.

Question 12

If productivity increased in a factory after all of its employees were switched to a work schedule consisting of four 10-hour days, should management really credit the schedule switch with the improvement?

Accepted Answer

There are many threats to validity that could have influenced the increase in productivity, so it would be difficult to attribute it solely to the schedule switch. Factors such as changes in management, new technology, or restructuring of responsibilities could have also contributed to the increase. Conducting further research, such as surveys or experiments, would be necessary to determine the true cause of the productivity increase.

Question 13

You survey a group of people who have just finished college, most of whom say that the experience was worthwhile and that they learned a lot. What experimental design does this represent?

Accepted Answer

This experimental design is a one-group posttest-only design because there is only one group being surveyed after experiencing a common event (finishing college). It does not involve any manipulation of variables or control groups.

Question 14

The one-group posttest-only design should be avoided because

Accepted Answer

The one-group posttest-only design should be avoided because there are many uncontrolled threats to validity. Without a comparison group, it is impossible to determine if any observed changes are due to the intervention or other factors such as history, maturation, or testing. This lack of control for external factors reduces the internal validity of the study.

Question 15

A researcher wonders about the memory performance of people with Parkinson 's disease, so he recruits 25 patients and gives them the CVLT, a standard memory test. He then gives 25 college students the same test, and compares the performance. What experimental design has he used?

Accepted Answer

This is a posttest only with nonequivalent control group design because the researcher has two separate groups (Parkinson's patients and college students) that he is comparing based on their performance on the CVLT test. There is no pretest or control group, and the groups are nonequivalent because they differ in terms of age and health status.

Question 16

You have a hypothesis that sugar decreases the ability to remember lists of words, and that this impairment increases with the amount of sugar that is administered. Design a between groups single factor true experiment to test this idea. Be sure to define your independent and dependent variables. How will you recruit subjects? How will you allocate subjects and conditions?

Accepted Answer

The answer of You have a hypothesis that sugar decreases...

Question 17

X O represents the

Accepted Answer

X O represents the one-group posttest only design, where X represents the treatment or intervention and O represents the posttest measurement of the outcome variable. In this design, there is only one group receiving the treatment, and their posttest scores are compared to the expected outcome based on prior research or theoretical predictions.

Question 18

A doctor prescribes a new drug for a sick patient. The patient gets well. Should the doctor believe that the drug made the patient well?

Accepted Answer

There are too many threats to validity to draw the conclusion that the drug made the patient well. This could be due to a placebo effect, natural recovery, or other factors. A single-factor experiment also does not account for the possibility of multiple factors contributing to the patient's recovery. Therefore, the doctor cannot definitively conclude that the drug was the sole factor in the patient's recovery.

Question 19

The experiment by Pinel on exploration as a function of Electroconvulsive Shock-learning interval used a multiple-condition design to

Accepted Answer

The experiment used a multiple-condition design to determine the shape of a function, specifically the relationship between the time interval between electroconvulsive shocks and subsequent exploration behavior in rats.

Quiz 10: True Experiments, Part 1 Single-Factor Designs