Chapter 13 2020 Research Methods

selection effects

Groups vary systematically on traits other than the levels of the independent variable.selection effects

history threat

An external event, rather than the independent variable, changes scores of the dependent variable.

True Statements(s) Patients who undergo such invasive surgeries are different from the general population, so there was a problem with external validity. The surgeon removed other areas of the brain in addition to the hippocampus, so there was a problem with internal validity. False Statement(s) Traditional statistics cannot be used to analyze small-N studies, so there was a problem with statistical validity. Variables cannot be manipulated accurately in small-N studies, so there was a problem with construct validity.

While small-N studies are highly impactful, there are also disadvantages of such designs. One advantage to the extensive research conducted on Henry Molaison, an individual who had several areas of his brain removed to treat seizures, is that it revealed the impact of the hippocampus on memory. Identify the true and false statements about the disadvantages to the small-N study of Henry Molaison.

nonequivalent control group interrupted time-series design

Work through the interactive, which charts the percentage of positive-emotion words used on Twitter over the course of 24 hours, each day of the week. Then answer the question that follows.

The reading program at High School A is known to be much more rigorous than the one at High School B. The posttest shows more improvement at High School A, but more students also dropped out of that program.

attrition threat

Asher is recording children's playground behavior to investigate the differences between third, fourth, fifth, and sixth graders. For each session, he sits on the swings with a notebook and counts the sizes of groups and types of activities for each grade. Asher notices that several children in each grade come over to the swings, but then walk away once they notice him sitting there. Because they walk away, they are not counted in the study. Asher finds that the younger grades tend to do more group activities, while the older grades tend to engage in more individual activities. What problem is affecting Asher's quasi-experiment?

demand characteristics

Researchers can use a double-blind study design.

demand characteristics

A group of researchers is measuring foot traffic in a museum. Recently, one half of the museum was redone in order to encourage more foot traffic. Researchers are counting the number of attendees in this new zone versus other zones that have not been redone. On the first day that researchers are recording foot traffic, several buses of schoolchildren arrive at the museum unexpectedly for a field trip. After a day of testing, the new zone appears to be getting just as much foot traffic as the other zones. What problem is most likely affecting this quasi-experiment?

history threat

- Researchers have some college students go through a mindfulness exercise while other college students watch a nature documentary. - Researchers examine the difference in behavioral problems between children whose parents were told to give positive reinforcements only and children whose parents were told to give punishments only.

independent variable

Researchers can use the same questionnaire multiple times to ensure that the standard is the same across measurements.

instrumentation threat

The school district employee who assessed the pretest was sick, so a new, less-experienced employee went to assess the posttest reading performance. Both groups show improvement in the posttest.

instrumentation threat

In quasi-experiments, researchers lack full experimental control. Therefore, which type of validity must they assess to make sure they can draw firm conclusions from their results?

internal

a quasi-experiment with a single group of participants that is measured repeatedly before, during, and after some event

interrupted time-series design

Gathercole and Baddeley (1990) examined phonologic memory skills in older children with disordered language development, using a control group comprised of typically developing younger children who were matched on verbal abilities.If they had done a follow-up study with the same participants a year later, which type of threat to internal validity would the difference in the participants' ages most likely have caused?

maturation

A psychologist is working with the parents of four siblings who exhibit violent behaviors toward one another. The psychologist instructs the parents to record the number of violent behaviors each child exhibits in the predinner hour for 1 week. The parents then begin using a positive reinforcement technique to shape the behavior of the youngest child. They continue to record the violent behaviors of all the children, and they use the positive reinforcement technique on one additional child each week. By the end of 6 weeks, there is a significant decrease in violent behaviors in each of the children. What type of design is this?

multiple-baseline

A company that owns several hospitals in rural areas of the South goes bankrupt and closes all its hospitals. Researchers become aware of this situation and use public health records to document the average age at death of residents in communities where the hospitals closed, and in other communities that were matched on several variables but did not lose their hospitals. The researchers collect death records in the two communities for several years before and after the closure of these hospitals to investigate the effect the closures had on life expectancy. What type of design are the researchers using?

nonequivalent control group interrupted time-series design

What research design is depicted in this interactive?

nonequivalent control group interrupted time-series design

a quasi-experiment with two groups that are measured repeatedly before, during, and after some event

nonequivalent control group interrupted time-series design

Select the figures that depict a nonequivalent control group interrupted time-series design.

nonequivalent control group interrupted time-series design -->

a quasi-experiment with one treatment and one control group that measures the dependent variable only once

nonequivalent control group posttest-only design

a quasi-experiment with a treatment and a control group that measures the dependent variable before and after the treatment

nonequivalent control group pretest/posttest design

- Researchers examine cultural differences in the expression of emotion between North Americans and the Japanese. - Researchers look at the difference between introverts and extroverts in displaying aggressive behavior after experiencing ostracism.

participant variable

What is the main difference between quasi-experiments and correlational studies?

quasi-experiments have more intentional samples such as targeted groups with particular qualities

- Researchers study the difference in binge-drinking episodes between cities with football teams that win and cities with football teams that do not win each weekend. - Researchers examine the difference in protective face mask-wearing behavior between states that have made mask-wearing mandatory and states that have not during the COVID-19 pandemic.

quasi-independent variable

Researchers can make sure to avoid selecting participants who produce extreme scores.

regression to the mean

The pretest reading scores are much higher at High School A than High School B. The posttest shows that High School A's reading scores decreased significantly.

regression to the mean

Researchers can make sure that participants in the control and treatment groups are matched on an important factor.

selection threat

High School B hosted a Math Olympiad competition, and students there spent a lot of time studying for math. In the posttest, High School A has greater improvement in reading

selection-history threat

Researchers are conducting a repeated-measures quasi-experiment that involves a single questionnaire that participants must complete weekly.Which type of threat to internal validity should concern the researchers if they notice the participants are taking less and less time to complete the questionnaire each week?

testing threat

Researchers can use a different test for the pretest and posttest to make sure that participants' change in performance is not due to practice or fatigue.

testing threat

Kanchi is interested in studying how water aerobics improves attitudes toward exercise over time. She recruits a group of participants who have signed up for a water aerobics course and measures their attitudes about exercise. She randomly assigns half of the participants to begin a weekly water aerobics class immediately and assigns the other half of participants to start taking the weekly aerobics class the following month. After all the participants have taken two months of aerobics, Kanchi measures their attitudes about exercise again. What design strategy is Kanchi using?

wait-list design

Nearly all small-N experiments are what type of design?

within-subjects

testing threats

Participants change their responses based on past assessment.

attrition threat

Participants leave a study in a systematic way.attrition threat

maturation threat

Participants show spontaneous change.

selection effects slection history

Two universities are involved in a study of how student retention and attitudes toward campus life are affected by a new pre-first-year summer visit program at one of the schools. The schools, both state universities in the same state, were closely matched in student-body characteristics to avoid the threat of selection effects. However, in the fall of the first year of the program, the school that was serving as the control was struck by a rare fall tornado, which did damage to several campus buildings. This event could lead to a(n) selection history threat

placebo effects

The thought of treatment, rather than the treatment itself, causes participants to report changes.placebo effects