Question 1

Which technique can be used to help reduce the threat to experimental mortality?

Accepted Answer

Shortening the time between the pretest and the posttest can help reduce experimental mortality by minimizing the chances of participants dropping out over time.

Question 2

Threats to internal validity in an experimental design can be minimized by _____.

Accepted Answer

Proper selection and assignment of subjects to groups can help control for potential confounding variables and increase the internal validity of the experimental design. While large sample size can also help with external validity, it does not necessarily address threats to internal validity. Small sample size can actually increase the risk of type II errors and limit the generalizability of the findings. While it may not be possible to completely rule out all threats to internal validity, taking steps to minimize them can improve the quality of the study.

Question 3

A questionnaire is sent to 1,000 police departments in Florida and gathers information on the number of sick days officers use after being involved in a shooting incident. This is an example of ____ research.

Accepted Answer

This is an example of case-oriented research, as it focuses on a specific group (police officers involved in shooting incidents) and the impact on their sick leave usage. It is not a variable-oriented study as it is not looking at the relationship between two variables, and it is not a quasi-experimental or cohort study as it is not manipulating any variables or following a specific group over time.

Question 4

Which statement is accurate?

Accepted Answer

Careful control of conditions helps to minimize extraneous variables that can affect the outcome of an experiment, thus reducing threats to internal validity. Threats to external validity, on the other hand, refer to the generalizability of the findings to other populations or settings, and cannot be fully eliminated but can be addressed through replication and the use of diverse samples. Option A is incorrect because controlling conditions typically addresses threats to internal validity. Option C is incorrect because while threats to generalizability exist, they can be addressed to some extent through sampling strategies and other design decisions. Option D is incorrect because threats to internal and external validity are distinct and can have different causes and solutions.

Question 5

You have just completed the LSAT and scored 85. Your roommate, who is no smarter than you, took the LSAT with you and scored 165. You were so upset with your score that you decide to take the test again and you convince your roommate to take it with you for moral support. You both receive scores on the second exam of 120. What accounts for the differences in scores?

Accepted Answer

The phenomenon of statistical regression can explain the differences in scores. This is the tendency for extreme scores to move toward the mean upon retesting. Since your initial score was significantly lower than your roommate's, it is more likely to regress toward the mean on the second test, while your roommate's score, which was already closer to the mean, will not have as significant of a change.

Question 6

Experimental mortality is especially likely to be a problem when ____.

Accepted Answer

Experimental mortality is more likely to occur when participants are required to put in effort or engage in difficult tasks. A lack of motivation or frustration can cause participants to withdraw from the experiment prematurely, potentially biasing the results. Option A is not necessarily related to experimental mortality, while options B and C do not provide enough information to determine if experimental mortality is likely to occur.

Question 7

If randomization is not possible, the researcher would be well-advised to ____.

Accepted Answer

If randomization is not possible, the best option is to switch to a quasi-experimental design. This type of design can still provide valuable information, even though it cannot guarantee causality in the same way a randomized design can. Pseudorandomization is a potential solution, but it may not be feasible or practical in all cases. Switching to a classical design would not address the issue of lack of randomization. Doing nothing and simply mentioning the issue in the research report would not address the potential biases introduced by the lack of randomization.

Question 8

External validity in an experimental design refers to _____.

Accepted Answer

External validity refers to the ability to generalize the findings of a study to other populations or settings. It is concerned with the extent to which the results obtained from a sample of subjects can be applied to a larger population of interest. The other options listed are not related to external validity.

Question 9

The history threat refers to the possibility that ____.

Accepted Answer

The history threat refers to the possibility that events external to the experiment that occurred between the pretest and posttest (or at any other time) will impact the results. This can include things like news events, policy changes, or other external factors that may influence the subjects' behavior during the course of the study.

Question 10

Which action would be most likely to result in selection bias?

Accepted Answer

Soliciting volunteers from a specific group, such as a college class, can lead to selection bias because the sample may not be representative of the population as a whole. People who choose to volunteer may have different characteristics or motivations than those who do not volunteer, which can affect the results of the study.

Question 11

In Widom's study of the effects of child abuse and its impact upon later criminal offenses, she selected a sample of children with court records of being abuse victims and gathered a comparison group that were matched on gender, race, age and socioeconomic status. The technique used in this case was ____.

Accepted Answer

The technique used in this case was individual matching since each abuse victim was matched with a comparison group member of the same gender, race, age and socioeconomic status, indicating a one-to-one matching process. Aggregate matching involves matching groups on certain criteria rather than individuals, while randomization involves assigning participants to groups at random. Probabilistic aggregation is not a recognized statistical technique.

Question 12

The maturation threat refers to _____.

Accepted Answer

The maturation threat refers to the impact of natural, developmental processes on experimental outcomes. This can be a threat to the internal validity of the study if the changes in the dependent variable are due to maturation rather than the manipulation of the independent variable. For example, if studying the effects of a new medication on blood pressure, but some participants naturally experience a decrease in blood pressure over the course of the study due to maturation, it could be difficult to determine the true effects of the medication.

Question 13

Neither the subjects nor the researcher can identify which group is the control group and which is the experimental group. Which design is being used?

Accepted Answer

The double-blind design is used to prevent bias, with neither the subjects nor the researchers knowing who is receiving the treatment and who is in the control group.

Question 14

When using a nonequivalent-groups design, the researcher will handle subject assignment to groups by ____.

Accepted Answer

In a nonequivalent-groups design, researchers often use matching to equate groups on certain variables because random assignment is not possible.

Question 15

Shortening the time between pretest and posttest or perhaps even offering cash payments to participants in an experiment are techniques that may be used to ____.

Accepted Answer

Shortening the time between pretest and posttest or offering cash payments are techniques to decrease experimental mortality, which refers to the loss of participants over the course of an experiment. This helps to ensure that the sample size remains consistent throughout the study, reducing the risk of bias or confounding variables. The other options are related to different sources of error in research design.

Question 16

Random assignment to experimental and control groups should reduce the threats to _____.

Accepted Answer

Random assignment helps control for the threat of maturation, which refers to changes occurring naturally in participants over time that may affect the outcome of the study. Random assignment does not directly address the threats of instrumentation, reliability, or small sample size.

Question 17

An interrupted time-series design can be very useful in ____ research.

Accepted Answer

An interrupted time-series design is a type of quasi-experimental design that is often used in applied research. This design is particularly useful when it is not feasible or ethical to conduct a randomized controlled trial (RCT), but we still want to evaluate the impact of an intervention or policy change. In an interrupted time-series design, we first collect data on a particular outcome variable for a period of time before the intervention or policy change (the baseline period), and then we collect data for a period of time after the intervention or policy change has been implemented (the intervention period). By comparing the trend in the outcome variable before and after the intervention, we can get an estimate of the intervention's causal effect.

Question 18

Experimental mortality is also known as ____.

Accepted Answer

Experimental mortality refers to the loss of participants in a study due to factors such as dropouts, withdrawals or death. It is also called attrition. Therefore, the correct option is C.

Question 19

_______________ validity is the correspondence between the empirical test of a hypothesis and the underlying causal process that the experiment is intended to represent.

Accepted Answer

Construct validity is concerned with how well an experiment represents the underlying theoretical construct that it is attempting to measure. It assesses the degree to which the measurement of a variable is related to the underlying theoretical construct being studied. Therefore, it is the best choice for the given scenario. Compensatory validity is not a recognized term in psychology research. Correlational validity is not pertinent here, as it refers to the degree to which two variables are related. Criterion validity is the degree to which a measure is related to an outcome.

Question 20

Graduates majoring in criminal justice and graduates majoring in psychology from the State University were part of a study to assess employment success of those receiving their degrees in May 2002. Six months after graduation November 2002 a questionnaire was sent out asking about their job seeking success. What type of design is this?

Accepted Answer

This is a cohort design because it involves following a group of individuals who share a common characteristic (in this case, graduation in May 2002 with specific majors) over a specified period to assess an outcome (employment success).

Quiz 5: Section 1: Experimental and Quasi-Experimental Designs