Question 1

Which of the following conditions would lead you to recommend against the use of a matched groups design and in favor of a random groups design?

Accepted Answer

When a large number of participants from a homogeneous population is available, random assignment is likely to create equivalent groups without the need for matching, making a random groups design more efficient and practical.

Question 2

A cognitive psychologist wants to do an experiment testing the memory of elderly people.She has the following constraints: only 12 people available as possible participants and the independent variable she is manipulating requires the use of separate groups for each condition.The psychologist has a reliable and valid pretest she plans to use.Which design is this psychologist likely to use?

Accepted Answer

Since the psychologist has only 12 participants available, a matched groups design would be the best option. This design involves matching participants on relevant characteristics before assigning them to different groups. In this case, the psychologist can use the pretest to match participants on their memory ability before assigning them to either the experimental or control group. This allows for greater control of extraneous variables, and more power to detect differences between the groups.

Question 3

When conducting an experiment using the matched groups design,the preferred pretest task (matching task)is

Accepted Answer

The preferred pretest task (matching task) in a matched groups design should be the same task that will be used as the dependent variable. This helps to ensure that any differences between the groups after the intervention can be attributed to the intervention itself and not to differences in the groups' abilities on the task. Using a completely different task or a task with limited reliability and validity would not provide a strong basis for matching participants, and using an inexpensive task that participants could complete quickly may not provide sufficient variability in performance to allow for meaningful matching.

Question 4

A researcher has read a research report indicating that a certain medication has been found to be effective when tested on men.The researcher plans to do an experiment testing the effectiveness of the same medication but in his experiment both men and women will be tested.The researcher is planning to do a

Accepted Answer

By including both men and women in the experiment, the researcher is partially replicating the original experiment to test the external validity of the finding. This will determine if the medication is effective not just for men, but also for women, and if the findings can be generalized to a wider population. Internal validity refers to the accuracy and control of the experiment, sensitivity refers to the ability to detect small differences or effects, and statistical power refers to the ability to detect true effects in statistical analysis, and these are not directly addressed by the researcher's plan.

Question 5

The natural groups design represents an illustration of the general research approach that is called

Accepted Answer

Natural groups design is a type of correlational research where researchers study pre-existing groups to find relationships between variables without manipulating them.

Question 6

Researchers found a relationship between insults and aggressive behavior for 5-year olds.If they want to test the external validity of the conceptual relationship between insults and aggressive behavior for a sample of 35-year olds,they should

Accepted Answer

Using age-appropriate insults and measures of aggression for 35-year olds would ensure that the study is valid for the older age group. Insults that are appropriate for 5-year olds may not be relevant or have the same impact on 35-year olds. Additionally, measures of aggression may need to be adjusted to reflect the different ways that adults express aggressive behavior compared to children. It is important to consider the developmental changes that occur as people age and adjust the study accordingly.

Question 7

Which of the following is the most critical problem in drawing causal inferences based on the natural groups design?

Accepted Answer

The most critical problem in drawing causal inferences based on the natural groups design is eliminating plausible alternative causes for the obtained relationship. Since participants are not randomly assigned to groups, there may be other factors beyond the natural grouping that could influence the outcome variable, making it difficult to establish causality. Therefore, it is important to consider and eliminate other potential explanations for the relationship between the grouping variable and the outcome variable. Establishing covariation, correlating participants' characteristics and their performance, and specifying the direction of the potential causal relationship are also important, but they are not as critical as eliminating plausible alternative causes.

Question 8

To differentiate experiments involving individual differences (subject)variables and those involving manipulated independent variables,those experiments involving individual differences (subject)variables are called

Accepted Answer

Experiments involving individual differences or subject variables are called natural groups designs because the groups are formed based on naturally occurring characteristics rather than manipulated variables.

Question 9

In what situation is it argued that external validity is irrelevant?

Accepted Answer

External validity is considered irrelevant when the purpose of the experiment is to test a specific hypothesis derived from a theory because the focus is on the internal validity and the theoretical implications rather than generalizing the findings to real-world settings.

Quiz 6: Independent Groups Designs

Which of the following conditions would lead you to recommend against the use of a matched groups design and in favor of a random groups design?

When conducting an experiment using the matched groups design,the preferred pretest task (matching task) is

The natural groups design represents an illustration of the general research approach that is called

Researchers found a relationship between insults and aggressive behavior for 5-year olds.If they want to test the external validity of the conceptual relationship between insults and aggressive behavior for a sample of 35-year olds,they should

Which of the following is the most critical problem in drawing causal inferences based on the natural groups design?

To differentiate experiments involving individual differences (subject) variables and those involving manipulated independent variables,those experiments involving individual differences (subject) variables are called

In what situation is it argued that external validity is irrelevant?