PSClearn 10

Participant variables a. can influence the dependent variable. b. cannot be manipulated. c. increase internal validity. d. are considered independent variables

A

Confounds are a threat to which of Mill's criteria for establishing causality? a. Covariance b. Elimination of alternative explanations c. Temporal precedence d. Participant variables

B

A researcher is concerned with confounding variables in a. a descriptive research design. b. all research designs. c. an experimental research design. d. a correlational research design.

C

Evaluate each question, read each answer choice carefully, and select the best answer. Please answer the following questions: 1. Which of the following threats to internal validity is the most difficult to prevent? a. Regression to the mean b. Contamination by communication c. Maturation d. Testing effect

C

Why might a researcher try to gather participants from various locations? a. To increase internal validity b. To prevent a history threat c. To prevent contamination by communication d. To provide varied experiences

C

Bryan is a fifth grade teacher studying the effects of lighting on reading speed. He has his morning class read with the shades drawn and the lights on, and his afternoon class read with natural sunlight. He finds that the natural light readers read faster. Identify the confound in Bryan's study and describe the potential effects of the confound.

Class meeting time may be a confounding variable. For instance, the afternoon class might be more alert or more attentive to the reading assignment.

A researcher was investigating how well a new antianxiety medication decreased anxiety for patients with moderate levels of anxiety. The participants in the experimental group were given the new medication, and participants in the control group were not. The researcher found a decrease in anxiety for the experimental group. If the participants might have had a decrease in anxiety because of their expectations about the effect of the medication and not the medication by itself, this would indicate which of the following possible threats to internal validity? a. Instrumentation b. Regression to the mean c. Testing effect d. Placebo effect

D

During an experimental study, all aspects should be equal for the groups except for the a. consent form. b. dependent variable. c. research setting. d. independent variable.

D

participant variables

characteristics such as age, gender, and intelligence that vary from one individual to another

double blind study

if both the participants and the researchers are unaware of the participant's condition

a study has high internal validity if it

is free of confounding variables

maturation

naturally occurring time-related changes in participants can influence the outcome of a study *more likely in longitudinal studies

elimination of alternative explanations

no confounding variable to explain the relationship between the independent and dependent variable

maturation can not be prevented

so it should be mentioned in findings

covariance

the independent variable and dependent variable are related

why are confounding variables troublesome

they act directly on the dependent variable, making it hard to conclude definitively that manipulation of the independent variable caused changes in the dependent variable

confounding variable

variable other than the independent variable that causes a change in the dependent variable

order effect

which is the influence of the order in which treatments are administered

A researcher finds that the average income of participants in her experimental group is higher than that of participants in her control group, so she switches some participants from the experimental to the control group before any data is collected. This is an example of a. balancing groups as a whole b. random assignment c. a matched-pairs design d. a homogenous sample

A

A researcher is concerned that participants may perform better at posttest simply because they completed the measure a second time and not from an improvement due to experiencing the independent variable. To prevent this practice effect, the researcher could a. eliminate the pretest. b. eliminate the posttest. c. add more experimental groups. d. add additional posttest measures.

A

A researcher is interested in investigating whether the presence of a night-light in a room has an effect on sleep quality. She asks participants in both the experimental and control groups to take a short nap in a darkened room in the laboratory, but for participants in the experimental group, she leaves a night-light on before exiting the room. The participants do not know of the night-light manipulation. This is an example of a __________ study. a. single-blind b. placebo c. poorly calibrated d. double-blind

A

Identify the appropriate method to prevent an instrumentation threat. a. Properly calibrate all measurement instruments. b. Remove physiological instruments from experiments. c. Select untrained observers to avoid bias. d. Conduct a double-blind study.

A

Which of the following internal validity threats does not apply to both within-group and between-groups designs? a. Order effect b. Maturation c. Confounding variables d. Testing effect

A

Why are confounds a concern in an experimental study? a. They make it unclear what was responsible for a change observed in the dependent variable. b. They cannot be controlled. c. They lower the study's construct validity. d. They lower the study's external validity.

A

A researcher is investigating the effectiveness of a new yoga program and assigns participants to either the experimental condition or control condition such that each person has an equal likelihood of being assigned to either condition. This strategy is called a. a matched-pairs design. b. random assignment. c. using a homogeneous sample. d. balancing groups as a whole.

B

A researcher is investigating the effectiveness of a smoking cessation program among middle-aged, college-educated White men who have been smoking cigarettes since they were teenagers. What strategy is the researcher using to eliminate confounding participant variables? a. Random assignment b. Homogeneous sample c. Balancing groups as a whole d. Block design

B

An instructor decided to test different study methods with the morning and afternoon sections of her research methods course. The morning section received instructions to study by rereading their notes, and the afternoon section received instructions to study by coming up with new examples of each term. Each section received the same test during their normal class period. Identify the confound. a. Research methods course b. Class time c. Type of study method d. Test

B

During pretest, a researcher presents participants with a group of digital three-dimensional mazes and measures completion time. The researcher then has participants engage in 30 minutes of aerobic activity. During posttest, participants complete the mazes again, and the researcher measures completion time. A testing effect would indicate that a. instrumentation was not reliable. b. completion time during the second test is changing due to repeated testing. c. the test was too difficult for participants to complete. d. the sample size is too small to detect a difference.

B

Fifty participants were randomly assigned to a physical activity group or a relaxation group during a research study examining self-control. The two research assistants conducting the study decided to split the workload so that one of them would test the experimental group participants and the other would test the control group participants. This study design is problematic because a. there are two independent variables. b. the research assistant conducting the test was different for each condition. c. there may have been a placebo effect. d. participants were not randomly assigned to the levels of the independent variable.

B

Identify the strength of within-group research designs. a. Eliminate all confounding variables b. Eliminate participant variables c. Increased external validity d. Eliminate the placebo effect

B

In an experimental design, why is it important that the groups have equivalent experiences? a. To make sure there are no differences in the independent variable. b. To be sure that any differences in participants' behavior relative to the dependent variable are due solely to differences in the independent variable. c. To ensure that random assignment was used. d. To make sure there are no differences in the dependent variable.

B

To avoid an internal validity threat from regression to the mean, researchers should a. train observers thoroughly. b. not select participants based on extreme pretest scores. c. include a placebo. d. always select participants with the highest pretest scores.

B

Which of the following illustrate contamination by communication? a. A researcher sees a past participant outside of the lab and discusses the research. b. A participant shares details about a research study with a future participant. c. A participant intentionally provides biased responses during an interview. d. A researcher accidentally discovers the purposes of the study and offers biased responses.

B

Why is it difficult to control for a history threat? a. History threats occur too rarely to control. b. History threats may involve unanticipated factors outside of a researcher's control. c. History threats occur too frequently to control. d. It would be too costly to control for history threats

B

a researcher designs a within-group experimental study to examine the influence of distractions on short-term memory. Explain why the researcher does not need to be concerned that age could be a confounding variable in her study

BC this is a within study group, each participant experiences both the control and experimental conditions. That means participant variables such as age would not differ between control and experimental conditions

A researcher designs a pretest-posttest study to measure test-taking time before and after participants learn a technique designed to promote more efficient, which means faster, test taking skills in a data analytics course. The control group, in a different section of the data analysis course but with the same instructor, completes the pretest and posttest, but does not learn the new technique. Describe a possible history effect.

Because the groups are taking the same course, it is possible they have other classes together as well. If so, imagine that they are all exposed to a test-taking workshop in a different class. The techniques learned are different from those in the study, but actually more effective. This means that any observed difference in the dependent variable between the control and experimental groups may be due to the test-taking workshop experienced by most (or all) of the experimental group participants and not manipulated learning technique.

A researcher had half of the participants begin with exposure to Condition A—a large computer monitor—and half of the participants begin with Condition B, a smaller computer monitor. Completion times for a data search and entry task were recorded following each condition. The design of this study includes _____, which can detect an order effect. a. participant variables b. random assignment c. counterbalancing d. a washout period

C

A researcher plans to study the effect of cardio exercise versus weight lifting on motivation. She randomly assigns half the participants to attend a weight-lifting class at the gym next door to the lab twice a week in 45-minute blocks and the other half to attend a cardio class at the same gym three times a week in 30-minute blocks. She then measures motivation each week over a 2-month period. A possible confound in this study is a. motivation. b. the type of exercise. c. the time spent in the gym. d. the difference in gyms.

C

A researcher was concerned that the research assistants she used to code the experimental videos in her study may have been coding for slightly different behaviors. If the experimental group behaviors were coded in a different way than the control group behaviors, this is an example of a. an external validity threat. b. a history threat. c. an instrumentation threat. d. the placebo effect.

C

During a drug trial, the experimental group receives a drug designed to decrease symptoms of anxiety and the control group receives a placebo. Which of the following would exemplify a history threat? a. The researcher does not use random assignment. b. All participants attend therapy sessions twice a week. c. The experimental group receives training in mindfulness during their checkups. d. Three participants in the control group do not return for the testing.

C

Using a within-group design, researchers were studying the influence of food with differing sugar content on participant energy levels. They planned to provide a food high in sugar content and measure participant energy levels 30 minutes later and provide a food low in sugar content and measure participant energy levels 30 minutes later. What should be included in the research design to increase internal validity? a. An order effect b. Additional levels of the independent variable c. A washout period d. A block design

C

A researcher conducted a within-group study to investigate the difference in spatial problem-solving between 5-year-old children when they were distracted and when they were not distracted. The group was presented with an online maze while having a cartoon playing next to them, and time to complete the maze was measured. After a 10-minute break, the same group of children was presented with a similar online maze while a colored screen appeared next to them, and time to complete the maze was measured. An example of an order effect would be if a. participants perform slower in the experimental condition because they were distracted. b. participants perform faster in the control condition because they were not distracted. c. participants do not differ in performance in the experimental and control conditions. d. participants perform faster in the control condition only because it was the second exposure to an online maze.

D

A researcher is investigating the effectiveness of various new medications to reduce alcohol cravings among a diverse group of participants. To eliminate confounding participant variables, the researcher splits the participant pool into 4 subsets of participants who are similar in age and weekly alcohol consumption. She then randomly assigns participants in each subset to take one of the 3 medications or the placebo. What strategy is she using to control for confounding participant variables? a. Matched-pairs design b. Homogeneous sample c. Balancing groups as a whole d. Block design

D

A researcher notes that a participant performs more poorly during the experimental condition compared with the control condition, but this difference is confounded with a change over time—fatigue. During the experimental condition, the participants had already been participating in the study for more than 1 hour. This threat to internal validity is known as a. regression to the mean. b. contamination by communication. c. history. d. maturation.

D

A researcher was interested in whether a new method of teaching fractions was more effective for student learning. She had an assistant randomly assign participants, who had no understanding of fractions, to either a new technique group or to an old technique group prior to testing. All participants then completed the same math test as a measure of their learning. In this scenario, neither the researcher nor the participants knew if they were assigned to the new technique group or the old technique group. This would be considered a _____ study. a. placebo b. single-blind c. poorly calibrated d. double-blind

D

A researcher who is trying to prevent contamination by communication could a. spread data collection over a long period so that participants would be less likely to recognize shared stories from the study. b. keep participant contact information private. c. keep participants isolated until the study is complete. d. ask participants not to discuss the study details with others during or after their participation in research.

D

After controlling for participant variables in an experimental study, a. random assignment will ensure equivalent experiences for groups. b. only the time of day must also be controlled. c. there is no reason to control for equal experiences between groups. d. a researcher must still control for equal experiences between groups during the experiment.

D

To investigate the effect of presentation format, a researcher randomly assigned participants to a video group or an audio group. The same information was presented for both groups; however, the format differed. The groups had an equal number of participants, but the video group had twice the number of male participants as the audio group. Recall of the presented material was measured for both groups. The confound in this example is a. the type of group. b. recall. c. presentation format. d. gender.

D

A researcher is examining the influence of a computer tutorial compared to self-instruction on learning to use a new iPad app and she is concerned that participant age might bias her study. Describe a way to ensure that the participant variable of age does not bias her study results.

If the researcher randomly selects and then randomly assigns her participants to groups, there should be an equivalent mix of ages in each group, which would neutralize the participant variable of age.

Erica is a professional baker who wants to determine whether she can reduce the fat in her recipes without sacrificing flavor. For one week, on random days, she cuts the fat in half when baking her famous muffins. She then uses an anonymous survey to ask her customers to rate the quality of the flavor of the muffin. Is there a clear confound in Erica's study?

There is no clear confound. There is no obvious confounding variable that would affect the outcome of this study. Data from the participants (regular muffin group and reduced-fat muffin group) are collected throughout the day, which eliminates any impact of the time of day. By randomly selecting days to change the recipe for one week, Erica is able to use multiple days for each group, which reduces the potential impact of any particular day.

A researcher recruited participants from the Introduction to Psychology participant pool at a small university. She had participants scheduled throughout the day over a two-week period of data collection. She noticed that participants during Week Two were behaving differently than participants from Week One as if they have had knowledge of what to expect during the study. How could this researcher have prevented possible contamination by communication? The four possible choices are: Choice A: She could have collected data in a shorter time. Choice B: She could have asked participants not to discuss the study with other individuals until the end of the two-week period after expaining that it could bias results. Choice C: She could have paid participants not to talk to other students for the next two weeks. Choice D: She could have forced participants to delete any social media apps on their phone until after data collection ended.

a and b

instrumentation

a change in the measuring device during the course of the study can be a confound if the instrument is poorly calibrated or malfunctions

balancing groups as a whole

after participants are randomly assigned to their experimental condition, but before they are exposed to the experimental condition, the researchers cam asses the group equivalencies in terms of one or more characteristics

using a homogeneous sample

all participants are highly similar, regardless of their assigned group --eliminates confounding participants variables which increases internal validity

random assignment

assignment of participants to the different conditions of an experiment is entirely at random so that each participant has an equal likelihood of being assigned to a condition

history effect

circumstances outside an experiment can influence the outcome which confound the experiment

A researcher is conducting a study on college students' willingness to get vaccinated against a common sexually transmitted infection. The researcher keeps the purpose of the study hidden from each participant until the end of their study session. A student who just finished a session sees his friend outside the lab waiting for her session to begin. He tells her about his experience in the session before hers starts. His friend now has an expectation of the purpose of the study. which threat to internal validity does this example illustrate?

contamination by communication

when we evaluate the internal validity of a causal claim we are ensuring that the study meets mill's criteria

covariance temporal precedence elimination of alternative explanations

washout period

extending the time between experimental conditions

regression to the mean

extremely high or extremely low scores naturally tend to become more moderate with repeated measurement of the dependent variable

which of the following is NOT a participant variable likely to impact the dependent variable of a study? -age -level of education -favorite color -gender

favorite color

A researcher is investigating whether using a mindfulness technique over the course of a semester reduces the stress experienced by 1st-year college students between the first and last month of their first semester. Participants in the experimental group practice mindfulness over the course of the semester, whereas participants in the control group do not. The researcher measures students' stress levels at the beginning and end of the study. However, a few days before the end of the study, a large fire in a dormitory destroys most of the students' belongings. Almost all of the students in the control group lived in this dorm, and results show that their stress levels are significantly higher than those of the students in the experimental group. which threat to internal validity does this example illustrate?

history effect

Q2: To avoid a confound, the researcher could conduct the entire study at one of the schools and assign some of the students in the school to receive the new initiative and other students to receive the traditional mode of instruction. which method is being used to control for the confounding variable?

homogeneous sample

an experiment is high in internal validity

if it provides compelling evidence that only manipulation of the independent variable and not bc of confounding variables

single blind

if only the participants are unaware of their condition

testing effect

if participants are tested multiple times, then practice or repetition of test items, tasks, or activities can influence participants' performance in subsequent tests

placebo effect

if participants have expectations of the effects of an experimental condition their expectations will confound the study

contamination by communication

if participants who have completed their research participation communicate their experiences to those who are waiting their turn to participate which can confound the study

A researcher who works for a company that makes heart pacemakers is testing the effectiveness of a new pacemaker on patients who survived a heart attack. Those in the control group use the old type of pacemaker, and those in the experimental group use the new pacemaker. The researcher tests the effectiveness of the two pacemaker types by administering an electrocardiogram (ECG). He tests the control group first and then tests the experimental group the following week. He has the ECG apparatus calibrated right before testing the control group but does not calibrate it again before testing the experimental group. The participants in the control group had more irregularities in their ECG results than participants in the experimental group. It is not clear whether the new pacemakers are more effective or whether the uncalibrated ECG did not pick up on the experimental participants' heart irregularities. which threat to internal validity does this example illustrate ?

instrumentation

any of the participant variables can lower

internal validity so they must make equal groups

A developmental psychologist is investigating whether having preschool children play a particular game (which involves waiting to receive a reward) helps them delay gratification. The psychologist has preschool children play the game twice a week for the entire school year, and then she tests the amount of time each child can wait to eat a piece of candy placed in front of him or her. At the end of the school year, the children waited significantly longer for the candy than they did at the beginning. However, it is unclear if this is a result of playing the game or children's naturally increasing ability to delay gratification longer as they get older. which threat to internal validity does this example illustrate?

maturation

placebo effect can threaten internal validity if

only the experimental group expects to see improvement

which of the following is a potential threat to internal validity if all participants are exposed to all conditions in the same sequence? Participant variables washout period order effect placebo effect

order effect

counterbalancing

participants are exposed to the levels of independent variable in different orders can be used to detect an order effect

Participants in the experimental group of a clinical trial for a new antianxiety drug expect the pill they are taking to relieve their symptoms. Those in the control group do not receive a pill and therefore do not expect their symptoms to decrease. The study finds that participants in the experimental group report fewer and less severe symptoms than those in the control group. However, it is not clear whether this effect is a result of the pill or of the expectations of those in the experimental group. Which threat to internal validity does this example illustrate?

placebo effect

A class of third graders is working on learning the multiplication tables. The teacher wants to try a new technique for teaching multiplication, so she tests her students individually on their ability to recite the multiplication tables from memory. She chooses the students in the lowest 5% of the class distribution of performance and uses the new technique to teach them how to remember the multiplication tables. After 1 month, the teacher retests her students and finds that those originally in the lowest 5% now have scores closer to the class average. However, the teacher cannot conclude that the new technique accounts for the improvement, because scores at extreme points of a distribution tend to get closer to the mean when they are retested. Which threat to internal validity does this example illustrate?

regression to the mean

use a match pairs design

researcher matches each participant in one group with a participant in another group who has similar characteristics on one or more specific variables

how to prevent regression to the mean

researcher should not select participants based on extreme scores

to prevent a confound from instrumentation

researchers should monitor and calibrate devices used for measurement

random selection

selection of participants from the population is random

Suppose you are conducting a clinical trial to test the effectiveness of a new group art therapy program for treating posttraumatic stress disorder (PTSD) in military veterans. You recruit qualifying participants from a local VA hospital and offer each individual the choice to participate in the art therapy program, which includes an hour-long group session once a week for 8 weeks. At the end of the 8-week program, you administer a PTSD assessment instrument to each individual and compare the scores of those who participated in the program (experimental group) with those who did not participate (control group). You find that those who participated in the program have lower PTSD scores than those who did not participate. What is the confounding variable? Select the best method to control for the confounding variable

self-assignment to the experimental and control groups random assignment

Suppose you want to know if people who have different severity levels of depression will benefit more from psychotherapy or hypnosis. You randomly assign participants to the psychotherapy group, the hypnosis group, or the control group. You find that hypnosis is more effective in reducing participants' symptoms of depression than psychotherapy. You are surprised by these findings because hypnosis is not typically used to treat depression. It is possible that the conditions were not balanced in terms of depression severity and that hypnosis was more effective because most of the participants in the hypnosis condition had lower levels of depression than those in the psychotherapy condition. what is the confounding variable?

severity of depression

to control contamination by communication

tell participants to not talk to each other

A researcher is testing whether individuals who smoke cigarettes perform better on a difficult puzzle task when they are not experiencing withdrawal from nicotine than when they are in withdrawal. He administers the puzzle task to participants after they have abstained from smoking for 8 hours and again the next day immediately after they have smoked. Overall the participants performed better the second time. However, it is not clear whether nicotine withdrawal had a negative effect on performance or whether participants' previous exposure to the puzzle task improved their performance the second time. which threat to internal validity does this example illustrate?

testing effect -to eliminate this the researcher can get rid of pretest

Suppose you are investigating whether a new behavioral intervention is effective in reducing symptoms in children who have autism spectrum disorder. From one school district you select children who were diagnosed with autism spectrum disorder—some children have severe symptoms (i.e., are very low functioning), others have milder symptoms (i.e., are relatively high functioning), and others are in between. You then randomly assign the children in your sample to either the control group (which will receive the current behavioral treatment) or the experimental group (which will receive the new behavioral intervention). What is the confounding variable?

the diagnosed severity level of autism

Suppose you want to investigate the effect of a new instructional tool on the math performance of eighth graders. You randomly select one school in the district to teach the new technique and another school in the same district to continue teaching math using the existing method. You find that the new initiative does, in fact, appear to have boosted students' math performance: The students who used the new instructional tool outperformed students at the other school on the same test of math skills. What is the confounding variable? Q1

the difference in schools

temporal precedence

the independent variable must be manipulated before there is a measured difference in the dependent variable

Darnell is the medical director for a hospital and wants to improve patient satisfaction with the quality of care given by the hospital staff. He asks the doctors in the orthopedic unit to use the name of each patient when they meet. Conversely, he asks the doctors in the cardiac care unit to avoid using patient names. He then compares the two groups' patients in terms of their scores on a satisfaction survey and finds that the patients whose names were used reported greater satisfaction than did those whose names were not used. Is there a clear confound in Darnell's study?

there is a clear confound. The difference in hospital units is a confounding variable that might contribute to different patient satisfaction. For example, it is possible that patients in the orthopedic unit are generally more satisfied with the quality of their care than patients in the cardiac unit.

Angela is investigating the potential relationship between exercise and depression. She randomly assigns her participants, whom she had previously randomly selected from a large group of college students, to an exercise group or to a no-exercise group. After the 3 weeks, she measures their level of depression and finds that the exercisers scored lower in depression that the non-exercisers. Is there a clear confound in Angela's study?

there is no clear confound