Psy 290 Ch 11
Frances investigated the effect of concreteness on memory. She created a list of 12 items that are very concrete (e.g., pencil and table) and a list of 12 items that are very abstract (e.g., justice and freedom). Each item was viewed for 1 second, then participants recalled them in order. Ten participants were randomly assigned to each list of items. The study showed null effects, and almost all the participants remembered all the words on both lists. Which is a likely solution? - Change to a posttest-only design. - Change the design to be double-blind. - Change the design to eliminate ceiling effects. - Change the design to be within-groups.
Change the design to eliminate ceiling effects FEEDBACK: If all the participants are getting all of the items correct, then Frances should make the task more difficult to eliminate the ceiling effect. See the section "Ceilings, Floors, and Dependent Variables" in your text for more information.
Emma is planning an experiment to examine whether reading to children increases their vocabulary size. She plans to measure the vocabulary size of a group of 18-month-old children, read to them three times a week for 3 months, then measure their vocabulary size again. Emma could change the design of the study to remove a major threat to internal validity by doing which of the following? - She could add a manipulation check. - She could make it a double-blind, placebo-controlled study. - She could counterbalance her conditions. - She could add a comparison group.
She could add a comparison group. FEEDBACK: Adding a comparison group would allow her to show her intervention had an effect beyond the normal effects of maturation. See the section "Maturation Threats to Internal Validity" in your text for more information.
Dr. Robinson designs an intervention meant to reduce college students' risky sexual decisions. She hypothesizes that shaming college students about their risky sexual decisions will improve their decision-making. She recruits participants and randomly assigns them to two conditions: the intervention group and the control group. The sexual behavior of all participants is measured in a pretest interview with Dr. Robinson. After the pretest interview, participants in the intervention group are scheduled for an individual shaming session with Dr. Robinson. The control group does not receive the shaming session. One week after the intervention, both groups are interviewed by Dr. Robinson about their sexual behavior during the past week. She finds that the intervention group reported less-risky sexual decisions than the control group in the posttest interview. In which way could Dr. Robinson improve the internal validity of her study? - She could make it a masked design. - She could make it a posttest-only design. - She could change the design to avoid ceiling effects. - She could change the design to be within-group.
She could make it a masked design. FEEDBACK: In this case, although it is not possible for the participants to be blind to their condition, it is possible to make the person assessing the dependent variable blind to group membership, which should make the students more likely to be honest. See the section "Controlling for Observer Bias and Demand Characteristics" in your text for more information.
Individual differences can contribute to too much within-group variability. Which of the following is a possible solution to individual differences? - Use an independent-groups design rather than a within-groups design. - Use a within-groups design rather than an independent-groups design. - Use a double-blind study. - Conduct a manipulation check.
Use a within-groups design rather than an independent-groups design. FEEDBACK: Within-groups designs compare each participant to himself or herself, so individual differences are controlled for. See the section "Individual Differences" in your text for more information.
Frances investigated the effect of concreteness on memory. She created a list of 12 items that are very concrete (e.g., pencil and table) and a list of 12 items that are very abstract (e.g., justice and freedom). Each item was viewed for 1 second, then participants recalled them in order. Ten participants were randomly assigned to each list of items. The study showed null effects and large variability within the groups. Which is a likely solution? - Add more participants. - Change the design to a posttest-only design - Change to a double-blind, placebo-controlled study. - Retrain the observers.
add more participants. FEEDBACK: Adding more participants to a study reduces the impact of individual differences within groups and will increase the chance of finding differences between groups. See the section "Individual Differences" in your text for more information.
Which threat to internal validity occurs when there is a greater systematic loss of participants in one condition than the other condition? - history - maturation - regression - attrition
attrition FEEDBACK: Attrition is not a threat if it occurs uniformly across both groups, but if it is systematic, it becomes a threat. See the section "Attrition Threats to Internal Validity" in your text for more information.
On the first exam in an Introductory Psychology class, the grades are lower than Professor Mutola expected. She suspects that multitasking is to blame. She bans computers and cell phones from her class between the first and the second exam. When she compares the scores on the two exams, she finds a significant improvement on the second exam. When Professor Mutola rechecks her data, she finds that the five students with the lowest scores on the first exam have dropped the class. Which threat to internal validity is this? - history - regression to the mean - maturation - attrition
attrition FEEDBACK: The rise in scores on the second test may be due to the loss of these extreme scores, which is attrition. See the section "Attrition Threats to Internal Validity" in your text for more information.
The students in Professor Zhao's 50-student Introductory Psychology class were randomly assigned to one of two review sessions, each being taught with a different technique. The next day, all 50 students got all 10 test questions correct. Which problem does Professor Zhao have in determining the better teaching technique for review sessions? - ceiling effect - confound acting in reverse - attrition - instrumentation
ceiling effect FEEDBACK: Because all the scores are squeezed together at the high end, the effect of the independent variable couldn't be measured. See the section "Ceiling and Floor Effects" in your text for more information.
Lucia is interested in studying discrimination in hiring. She designs an experiment in which the participant takes the role of an employer looking at job candidates for a specific position. Each participant is given two very similar résumés (one of a candidate with a female name and one of a candidate with a male name) and is then asked to rate the suitability of each candidate for a job. Lucia finds no difference in participants' ratings of male and female candidates. Which threat to internal validity should she be concerned about? - observer bias - demand characteristics - placebo - selection
demand characteristics FEEDBACK: Lucia should be concerned that the participants guessed the manipulation in the study and gave what they thought was the more socially acceptable answer. See the section "Demand Characteristics" in your text for more information.
Frances conducted a study on the concreteness on memory in her dorm. She created a list of 12 items that are very concrete (e.g., pencil and table) and a list of 12 items that are very abstract (e.g., justice and freedom). Each item was viewed for 1 second, then participants recalled them in order. Ten participants were randomly assigned to each list of items. The study showed null effects. Which is a possible explanation for this null effect? - external distractions that lead to unsystematic variability - too much between-group difference - not enough within-group variability - participants dropping out in only one condition
external distractions that lead to unsystematic variability FEEDBACK: Situation noise, or external distractions to the study, can increase variability within groups to obscure true group differences. See the section "Interrogating Null Effects: What If the Independent Variable Does Not Make a Difference?" in your text for more information.
A city in California has asked Professor Rodriguez to conduct an experiment on earthquake preparedness. Professor Rodriguez will assess the preparedness of a random sample of residents in the city and the city will mail out their annual brochure on earthquake safety. Then, 2 weeks later, he will again assess the preparedness of those residents. Right after the brochures are mailed, a large earthquake is reported in Japan. Which threat to internal validity does this pose? - selection - testing - history - maturation
history FEEDBACK: The earthquake is an external or "historical" event that occurs to everyone in the study; therefore, the effect of the brochure cannot be assessed. See the section "History Threats to Internal Validity" in your text for more information.
If everything else is equal, which of the following methods can help increase power in a study? - using an independent-groups design - increasing sample size - adding situation noise - adding a comparison group
increasing sample size FEEDBACK: Adding more participants to a study can increase power, or the ability to detect small or large effects in a study. See the section "Another Name for These Solutions: Power" in your text for more information
In an experiment on improving children's handwriting, two different techniques of improving handwriting and a control condition are used. Using a pretest/posttest design, both groups who received the treatment showed more improvement than the control group. However, the two groups didn't show any difference from each other. The researcher believes there is a difference but that the 5-point assessment scale of handwriting cannot detect it. Which measurement problem is the researcher concerned with? - measurement error - design confounds acting in reverse - weak manipulations - insensitive measures
insensitive measures FEEDBACK: The scale does not have the precision to detect the differences between the two treatments (the two handwriting technique groups). See the section "Insensitive Measures" in your text for more information.
On the first exam in an Introductory Psychology class, the grades are lower than Professor Mutola expected. She suspects that multitasking is to blame. She bans computers and cell phones from her class between the first and the second exam. When she compares the scores on the two exams, she finds a significant improvement on the second exam. Professor Mutola looks back over the second exam and begins to wonder if it was just an easier exam. Which threat to internal validity is she considering? - instrumentation - history - maturation - testing
instrumentation FEEDBACK: Instrumentation threat occurs when the pretest and posttest are not sufficiently equivalent. See the section "Instrumentation Threats to Internal Validity" in your text for more information.
As part of an experiment on the effects of behavior modeling, a set of raters are evaluating prosocial behavior in a series of videotapes of a preschool class. Initially, the raters were quite strict in their ratings, but after 3 hours of rating, their criteria had changed. Which type of threat to internal validity has occurred? - instrumentation - testing - history - regression to the mean
instrumentation FEEDBACK: The raters, who are the measuring instrument, are changing over time. See the section "Instrumentation Threats to Internal Validity" in your text for more information.
Which two types of validity in an experiment can observer bias threaten? - internal validity and external validity - construct validity and statistical validity - internal validity and construct validity - statistical validity and external validity
internal validity and construct validity FEEDBACK: Observer bias threatens internal validity because an alternative explanation for the results exist. Observer bias also threatens construct validity of the dependent variable because the ratings are inaccurate. See the section "Observer Bias" in your text for more information.
Emma is planning an experiment to examine whether reading to children increases their vocabulary size. She plans to measure the vocabulary size of a group of 18-month-old children, read to them three times a week for 3 months, then measure their vocabulary size again. Which threat to internal validity should she be most concerned about? - instrumentation - maturation - demand characteristics - order effect
maturation FEEDBACK: At 18 months, toddlers are rapidly increasing their vocabularies, so even without being read to, they would show an increase. See the section "Maturation Threats to Internal Validity" in your text for more information.
On the first exam in an Introductory Psychology class, the grades are lower than Professor Mutola expected. She suspects that multitasking is to blame. She bans computers and cell phones from her class between the first and the second exam. When she compares the scores on the two exams, she finds a significant improvement on the second exam. Professor Mitchell points out that in her classes, students always do better on the second exam because they are more used to her tests. Which threat to validity is Professor Mitchell suggesting? - attrition - regression to the mean - maturation - testing
maturation FEEDBACK: The students' scores may have risen, even if they had been multitasking, just because they had adjusted to the class. See the section "Maturation Threats to Internal Validity" in your text for more information.
Some internal validity threats can be addressed simply by including a comparison group, whereas other internal validity threats can occur even in studies with a comparison group. Which of the following threats to internal validity would be improved with the inclusion of a comparison group? - demand characteristics - maturation threats - placebo effects - observer bias
maturation threats FEEDBACK: A comparison group can be used to control for maturation threats; the changes in the treatment group that differ from those in the comparison group can be ascribed to the treatment. See the section "Preventing Maturation Threats" in your text for more information.
Which of the following contributes to within-groups variability? - measurement error - ceiling and floor effects - design confounds acting in reverse - null effect
measurement error FEEDBACK: Measurement error in the dependent variable will result in scores that are more spread out within a group (i.e., increased within-groups variability). See the section "Perhaps Within-Groups Variability Obscured the Group Differences" in your text for more information.
On the first exam in an Introductory Psychology class, the grades are lower than Professor Mutola expected. She suspects that multitasking is to blame. She bans computers and cell phones from her class between the first and the second exam. When she compares the scores on the two exams, she finds a significant improvement on the second exam. Which of the following is the name for this type of design? - one-group, posttest only - one-group, pretest/posttest - two-group, posttest only - two-group, pretest/posttest
one-group, pretest/posttest FEEDBACK: Professor Mutola is using the first exam as the pretest and the second as the posttest. See the section "The Really Bad Experiment (A Cautionary Tale)" in your text for more information.
Jared is conducting an experiment with extrasensory perception (ESP) training. He begins with a pretest of his 40 participants and then divides them into two groups based on their scores. The participants with the 10 lowest scores are given extensive training on how to detect the signals. The participants with the 30 highest scores are given no training. Both groups are retested and the average score of the participants with the training improved, whereas the average score of the participants without the training fell. Which threat to internal validity should Jared consider? - regression - maturation - history - attrition
regression FEEDBACK: The group given training had an unusually bad performance on the pretest, so it was likely to regress upward in performance on the posttest, even without training. See the section "Regression Threats to Internal Validity" in your text for more information.
Dr. Harrison wants to test the effectiveness of the support group he runs for undergraduates who have drinking problems. He recruits a group of students who have been referred to the counseling center. He randomizes them to two groups: a structured-session group and an unstructured-session group. The structured-session group attends 10 structured support-group sessions at 8:00 a.m. on Fridays that are facilitated by Dr. Harrison. The unstructured-session group attends 10 unstructured meetings at 3:00 p.m. on Wednesdays that are facilitated by members of the group. Several of the participants in the structured-session group stop attending after just a couple of sessions. All the members of the unstructured-session group attend their meeting regularly. At the end of the 10 weeks, Dr. Harrison measures drinking behavior of the people who are still attending the groups. He finds the drinking behavior of people who attended all 10 structured-group sessions is less than the drinking behavior of people who attended all 10 unstructured-group sessions. Which kind of threat to internal validity should Dr. Harrison be concerned about? - selection-attrition threat - selection-history threat - maturation threat - regression threat
selection-attrition threat FEEDBACK: Only one of Dr. Harrison's groups experienced attrition. Those who dropped out of his structured-session group may very well have been those with the worst drinking problems. See the section "Combined Threats" in your text for more information.
An instructor hypothesizes that doing jumping jacks will improve his students' quiz performance. On Monday, he has his class sit in their chairs for 5 minutes before completing a multiple-choice quiz on their reading assignment. On Wednesday, he has his class do 2 minutes of jumping jacks before completing the same quiz that they took on Monday. The students performed better on the quiz on Wednesday. Which is a possible threat to internal validity in this study? - observer bias - testing - maturation - attrition
testing FEEDBACK: Because the students are taking the same quiz just 2 days later, they might have done better because of their previous experience with the quiz. See the section "Testing Threats to Internal Validity" in your text for more information.
Which of the following is a problem that may contribute to a null effect in a study? - placebo effect - weak manipulations - too much power - large sample size
weak manipulations FEEDBACK: Weak or ineffective manipulation of the independent variable may not be strong enough to bring a change in the dependent variable and, thus, can obscure a true causal relationship. See the section "Perhaps There Is Not Enough Between-Groups Difference" in your text for more information.
