Question 1

A researcher exposes people to a stressful situation (such as public speaking) to examine the effect of stress on depressed mood. The researcher includes a measure of stress as a ____.

Accepted Answer

A manipulation check is used to determine if the experimental manipulation (in this case, exposure to a stressful situation) effectively induced the intended condition (stress) among the participants. This helps to verify that any observed effects on the dependent variable (depressed mood) can be attributed to the manipulation of the independent variable (stress).

Question 2

In an experiment comparing two treatments, the researcher assigns participants to treatment conditions so that each condition has 10 adults with college degrees and 10 adults with high-school diplomas only. For this study, what method is being used to control participant education level?

Accepted Answer

The method being used is matching, as participants are being assigned to conditions based on a specific characteristic (education level) to control for its potential influence on the outcome. Randomization involves randomly assigning participants to conditions without regard to specific characteristics. Holding constant involves keeping a variable constant across all participants, which is not the case in this study. Limiting the range involves only selecting participants within a certain range of a variable, which is also not the case in this study.

Question 3

In an experiment, a confounding variable is a(n) ____.

Accepted Answer

A confounding variable refers to any variable that is not the independent variable but has an effect on the dependent variable, making it difficult to determine if the effect observed is due to the manipulation of the independent variable or the confounding variable. This is a threat to internal validity and can undermine the validity of the experiment.

Question 4

Holding a variable constant is a technique for removing one threat to ____ but it can limit the ____ of an experiment.

Accepted Answer

Holding a variable constant helps to increase the internal validity of an experiment by reducing the possibility of confounding variables affecting the results. However, this can limit the external validity of the experiment by not allowing for the generalizability of results to different settings or populations.

Question 5

A researcher designs a study to determine whether female preschoolers prefer sweetened or unsweetened cereal. The researcher uses a box of sweetened colorful cereal and a box of unsweetened tan colored cereal. The research finds that the group of preschoolers ate more of the sweetened colorful cereal and therefore prefers the sweetened cereal. Which two variables are confounded in this experiment?

Accepted Answer

The two variables that are confounded in this experiment are the color of the cereal and the sweetness of the cereal. This is because the two variables are not independent of each other. The sweetened cereal happens to be colorful, while the unsweetened cereal happens to be tan in color. Therefore, it is impossible to determine whether the preschoolers preferred the cereal because of its color or its sweetness.

Question 6

What is the purpose for using a control condition in an experiment?

Accepted Answer

Using a control condition in an experiment provides a baseline against which to evaluate the size of the treatment effect. For example, if participants in the treatment group show a statistically significant improvement in a particular outcome measure compared to the control group, it suggests that the treatment had a positive effect. Without a control condition, it would be difficult to determine whether any changes seen in the treatment group were due to the intervention or some other factor.

Question 7

Which characteristic is necessary for an extraneous variable to become a confounding variable?

Accepted Answer

For an extraneous variable to become a confounding variable, it must change systematically when the independent variable is changed. In other words, it must be related to the treatment or intervention being applied in the study. This relationship between the extraneous variable and the independent variable can cause confusion when trying to determine the true effect of the independent variable on the dependent variable, hence confounding the results.

Question 8

What is the advantage of a simulation compared to a traditional laboratory study?

Accepted Answer

Simulations allow for the manipulation of variables in a controlled environment that closely mimics the real world. This can increase the external validity of the study, meaning that the findings are more likely to generalize to real-world situations compared to traditional laboratory studies, which can suffer from artificiality and low external validity. However, simulations may not necessarily have increased internal validity, as there may still be confounding variables that are not accounted for in the simulation. Simulations also do not necessarily eliminate history effects, as these can still occur within the simulation.

Question 9

A researcher attempts to recreate the real world in the laboratory. This type of research is called a ____.

Accepted Answer

This type of research is called a simulation study, as researchers attempt to recreate the real world in a controlled environment.

Question 10

Dr. Sian varies the amount of a new sedative given to three groups of participants (0, 1, and 2 mg) and then observes the reaction for each group. The 0-mg condition represents the ____ condition.

Accepted Answer

The 0-mg condition represents the no-treatment control condition, as this group does not receive the experimental sedative and is therefore not part of the manipulation or experimental condition. The manipulation check is typically used to ensure that the manipulation of the independent variable is effective and has the intended effect on the dependent variable. The waiting-list control is a type of control group often used in clinical trials, where participants are placed on a waiting list to receive the experimental treatment at a later time.

Question 11

Researchers often use simulation experiments in an attempt to obtain the ____ of an experiment and still keep much of the ____ of research conducted in the real world.

Accepted Answer

Simulation experiments focus on maintaining internal validity, which refers to the accuracy and reliability of the findings within the given experiment. However, in order to maintain internal validity, researchers often sacrifice external validity, which is the ability to generalize the findings to the real world. Therefore, simulation experiments prioritize internal validity while still attempting to keep some aspects of real-world research. Option C and D refer to the level of realism in the experiment and are not directly related to internal versus external validity.

Question 12

A researcher moves an experiment out of the laboratory and into the real world. This type of research is called a ____.

Accepted Answer

A field study is research conducted in a natural setting or real-world environment, rather than in a controlled laboratory setting. Simulation studies involve creating artificial environments to study a particular phenomenon, transported studies involve replicating a laboratory experiment in a different location, and quasi-experimental studies lack random assignment to experimental conditions.

Question 13

In an experiment, participants are usually assigned to treatments using random assignment. The reason for using random assignment is ____.

Accepted Answer

Random assignment helps control for extraneous variables by ensuring that participants are randomly assigned to the different treatment groups. This reduces the likelihood that any preexisting differences between participants will influence the results of the study. Random assignment does not typically involve manipulating participant or environmental variables, nor does it directly affect the reliability of the outcome measures.

Question 14

Although field studies tend to have higher external validity that traditional laboratory studies, they also tend to have ____.

Accepted Answer

Field studies often involve more complex and variable environments, which can make it difficult to control extraneous variables and ensure that the observed effects are truly due to the manipulation being studied. Therefore, they tend to have lower internal validity compared to laboratory studies.

Question 15

An experiment includes a treatment condition, a no-treatment control, and a placebo control. Which two conditions should be compared to determine the size of the effect that is actually caused by the treatment?

Accepted Answer

The answer of An experiment includes a treatment condition, a...

Question 16

What is the primary goal for randomly assigning participants to treatment conditions in an experiment?

Accepted Answer

The answer of What is the primary goal for randomly...

Question 17

In an experiment, participants are randomly assigned to treatment conditions ____.

Accepted Answer

Randomly assigning participants to treatment conditions helps protect the internal validity of the study because it ensures that any differences between groups are due to the treatment and not other extraneous variables. While it may also have some impact on external validity, its primary purpose is to ensure the accuracy and validity of the study's results.

Question 18

Which technique provides useful information when there are small changes from one treatment condition to another, when simulations are used or when a placebo is used?

Accepted Answer

Manipulation checks are used to ensure that the experimental manipulation has worked as intended. This provides useful information when there are small changes from one treatment condition to another, when simulations are used or when a placebo is used. Therefore, D is the best choice.

Question 19

A researcher decides to use only participants that weigh between 150 and 160 pounds in an experiment comparing two treatment conditions. For this study, what method is being used to control participant weight?

Accepted Answer

Holding constant involves controlling a variable by keeping it the same for all participants in a study. In this case, the researcher is controlling participant weight by only including individuals who weigh between 150 and 160 pounds, thus keeping the weight variable constant across the study.

Question 20

In an experiment, a researcher manipulates people's mood to determine whether changes in mood cause changes in memory performance. However, the researcher is not sure that the manipulation is really causing people's mood to change. In this case, what should the researcher do?

Accepted Answer

Adding a manipulation check by measuring mood would help the researcher confirm whether the manipulation is really causing changes in people's mood. This would allow the researcher to determine whether any observed changes in memory performance can be attributed to changes in mood or to some other factor. Controlling or matching mood across treatment conditions, or adding a no-treatment control group, would not address the issue of whether the manipulation is truly effective in changing mood.

Quiz 7: The Experimental Research Strategy