Question 1

Which of the following is a threat to external validity?

Accepted Answer

Specificity of variables threatens external validity because it refers to how the study's variables or conditions might not be applicable or generalizable to other situations, populations, or times. This can limit the ability to generalize the findings beyond the specific context of the study.

Question 2

Gavin's study compared reading error rates and reading comprehension scores between two groups of 50 third-grade students that received different reading programs. The treatment variable in Gavin's study is

Accepted Answer

The treatment variable in Gavin's study is the type of reading program the students received. This is the only variable that was intentionally manipulated by the researcher to test its effect on the dependent variables (reading error rates and comprehension scores). Therefore, the correct answer is C) reading instruction.

Question 3

The threat to validity defined as the effects of the occurrence of events that are not part of the treatment but affect the dependent variable is

Accepted Answer

History refers to events that occur during the study that are not part of the treatment but impact the dependent variable. This can include external events, changes in societal norms, or other factors that can influence the outcome of the study. Testing refers to the impact of pre-test or multiple measurements on the dependent variable, statistical regression refers to the tendency for extreme scores to move towards the center, and instrumentation refers to changes in how the dependent variable is measured.

Question 4

Treatment variable is another name for

Accepted Answer

Treatment variable refers to the independent variable, which is the variable that is manipulated by the researcher in order to determine its effect on the dependent variable.

Question 5

Consider the example of Roy, a researcher who studies the role of worked examples in engineering education. He measures students test performance and ratings of their instructors. He randomly assigns classes to condition. The independent variable in Roy's research is

Accepted Answer

The independent variable in Roy's research is the exposure to worked examples, as this is the variable that is being manipulated and tested in the study. The other variables, such as engineering education, test performance, and teacher ratings, are either background variables or dependent variables that are being measured in relation to the independent variable.

Question 6

A researcher's efforts to remove influence of variables other than the independent variable is referred to as

Accepted Answer

Control refers to the researcher's efforts to remove the influence of variables other than the independent variable. This is typically done through experimental design and controlling for extraneous variables. Assignment refers to how participants are assigned to different treatment conditions, sorting is not a commonly used term in research, and determination does not relate to removing influence of variables other than independent variable.

Question 7

The final step in an experimental study is the

Accepted Answer

The final step in an experimental study is to draw conclusions based on the data collected during the execution of procedures. While selecting and defining a problem, executing procedures, and analyzing data are all important steps in the experimental process, the ultimate goal is to formulate conclusions that can be used to inform future research or real-world applications. Therefore, choice C, formulation of conclusions, is the best answer.

Question 8

Replications in experimental research are generally conducted to facilitate

Accepted Answer

Replications in experimental research are generally conducted to facilitate external validity. This means they help to ensure that the findings of a study can be generalized to other settings, populations, or times beyond the original experiment.

Question 9

A laboratory study compared learning from text in two conditions, one with underlining of important terms and one without underlining, found that the underlining group did better on factual items. Marina then conducted a study with tenth-grade history students and compared one group that read a chapter with the important text underlined and one group that read a chapter without any underlining. Marina's study illustrates an example of a(n)

Accepted Answer

Marina's study is a replication study because it is a repeat of a previous study that examined the same research question and manipulated the same independent variable (underlining of important terms) to examine its effects on learning from text. This type of study is important to strengthen the validity of the previous findings by confirming or refuting them. The other options (A, B, and D) do not accurately describe Marina's study.

Question 10

In experimental studies, the sample may be derived from

Accepted Answer

In experimental studies, the sample is typically derived from one population. This allows researchers to control for variables and make causal claims about the relationship between variables. Using a sample from multiple populations could introduce confounding variables and make it difficult to draw clear conclusions about causality.

Question 11

The type of validity concerned with whether findings can be generalized to other groups or other settings is referred to as

Accepted Answer

External validity refers to the ability to generalize findings to other groups, situations, or settings. Internal validity refers to the extent to which the study design and methods accurately measured what they were intended to measure within the study sample. Content validity refers to the degree to which a measure or assessment tool covers all the relevant aspects of the concept being measured. Construct validity refers to the degree to which a measure accurately assesses the underlying construct it is intended to measure.

Question 12

Which of the following is a threat to internal validity?

Accepted Answer

Differential selection of participants is a threat to internal validity because it can lead to differences between the treatment and control groups that are not due to the treatment itself. For example, if the treatment group is more likely to be composed of people who are motivated to change, then the treatment may appear to be more effective than it actually is.

Question 13

The type of validity concerned with whether differences between groups are due to the manipulation of the independent variable is referred to as

Accepted Answer

Internal validity refers to the extent to which a study is free from errors and confounds that could affect the results. In the context of experimental research, it specifically refers to whether the observed differences between groups can be attributed to the manipulation of the independent variable, rather than any other factors. External validity refers to the extent to which the results of a study can be generalized to other populations or situations. Content validity refers to the extent to which a measure represents all the facets of a particular construct. Construct validity refers to the extent to which a measure assesses the underlying construct it is intended to measure.

Question 14

Gavin's study compared reading error rates and reading comprehension scores between two groups of 50 third-grade students that received different reading programs. His t test data analysis did not indicate any differences between the two types of instruction. The most likely reason for his findings is that

Accepted Answer

The most likely reason for Gavin's findings is that his groups were too similar. This means that both groups received similar instruction, which led to similar performance on reading error rates and comprehension scores. It is possible that with a larger sample, differences between the two types of instruction could have emerged. However, given the information provided, D is the best choice.

Question 15

Consider the example of Roy, a researcher who studies the role of worked examples in engineering education. He measures students test performance and ratings of their instructors. He randomly assigns classes to condition. Roy argues that his research is experimental. However, you argue that it is quasi-experimental given the following reason.

Accepted Answer

Randomly assigning intact groups is a characteristic of quasi-experimental design, not experimental design. In experimental design, individual participants are randomly assigned to conditions.

Question 16

Patsy conducted an experiment that included two groups of junior high girls. One group received no training while the other received a 3-hour intervention about the benefits of careers in math and science domains. Patsy compared the willingness of girls to enroll in subsequent math courses as her outcome measure. Her t test analysis indicated no differences between her treatment group and the no-exposure control. This finding is likely due to

Accepted Answer

Limited treatment exposure is a plausible reason for not observing a difference between the treatment and control groups. A 3-hour intervention might not be sufficient to change attitudes or behaviors significantly regarding enrolling in subsequent math courses.

Question 17

Marcy is concerned that her findings may be due to an extraneous uncontrolled variable and not her treatment. Marcy is most concerned with

Accepted Answer

Marcy's concern about an extraneous variable affecting the results suggests that she is worried about the internal validity of her study. Internal validity refers to the extent to which a study accurately measures the relationship between the independent variable (treatment) and the dependent variable (outcome) without any interference from external factors (extraneous variables).

Question 18

Compared to all other types of research, experimental research

Accepted Answer

Experimental research is designed specifically to investigate cause and effect relationships between variables. Therefore, it is considered the best type of research for determining causality. Option A is incorrect as the number of participants required depends on the specific experiment being conducted. Option C is true but is not unique to experimental research. Option D is referring to generalizability, which is not a unique feature of experimental research.

Question 19

Laura was conducting a study on two treatment interventions to increase patriotism. During her study, terrorist attacks on a federal building occurred. Laura should be concerned with which of the following validity threats?

Accepted Answer

The terrorist attacks on a federal building represent a historical event that could impact the results of the study. This is known as the history threat to validity. It is possible that the attacks could have affected participants' levels of patriotism, regardless of the intervention they received. Therefore, Laura should be concerned with this potential confounding variable when interpreting her results.

Question 20

In experimental studies, but NOT in other studies,

Accepted Answer

In experimental studies, the researcher manipulates the independent variables in order to observe the effect on the dependent variable. In other types of studies, such as observational or correlational studies, the researcher does not manipulate variables but simply observes them.

Quiz 10: Experimental Research