Question 1

If each subject in an experiment has an equal chance of being in the experimental group,then the experiment has

Accepted Answer

Random assignment means that each subject has an equal chance of being in the experimental group, which helps control for extraneous variables and increases the likelihood that any differences observed between groups can be attributed to the independent variable. Demand characteristics refer to cues that may influence participants to behave a certain way, and are not necessarily related to the method of group assignment. Correlation and statistical significance are not relevant to the concept of group assignment.

Question 2

How does an experimenter try to equate the experimental group and the control group at the start of the experiment?

Accepted Answer

Random assignment is the best way for an experimenter to equate the experimental and control groups at the start of an experiment. This involves randomly assigning participants to either the experimental or control group, which helps ensure that both groups are balanced in terms of potential confounding variables. Elimination of independent variables and demand characteristics are not methods used to equate groups, and statistical tests are used after data collection to analyze the results.

Question 3

Professor Middlebrain notes that rats in the first 10 cages,which were injected with salt water,are calm.Rats in the last 10 cages,which were injected with distilled water,are aggressive.He concludes that salt decreases aggressiveness.What is wrong with this study?

Accepted Answer

The study lacks random assignment, which means that the rats in the first 10 cages and the rats in the last 10 cages may have inherently different characteristics that affect their behavior, rather than the injection of salt water or distilled water. Therefore, it is not appropriate to draw a conclusion about the effect of salt on aggressiveness based on this study.

Question 4

The advantage of randomly assigning participants to the experimental group and the control group is that random assignment

Accepted Answer

Random assignment reduces the possibility that the groups differ greatly at the start of the experiment, which is important for eliminating or reducing the influence of independent variables. Option A is incorrect because random assignment does not guarantee that participants will know what is expected of them in the experiment. Option B is incorrect because statistical tests are still necessary to determine the significance of the results.

Question 5

Psychology experiments have typically shown that

Accepted Answer

Numerous psychology experiments have consistently shown that watching violent media, such as films, increases aggressive behavior at least temporarily. This is known as the "media violence effect." Other options are not supported by empirical evidence.

Question 6

Research participants viewed either violent or nonviolent films for four consecutive nights.On the fifth night,half the participants were told by the experimenter that their performance was terrible and the other half were told they had done well on some task.What group showed the most hostility on the fifth night?

Accepted Answer

The group that watched violent films and were told their performance was terrible showed the most hostility on the fifth night. This is because the combination of exposure to violence and negative feedback likely contributed to increased aggression. The other groups, including the group that watched violence but received positive feedback and all participants who were told their performance was terrible, may have also experienced increased aggression to some degree, but the combination of violent film exposure and negative feedback was likely the most potent factor.

Question 7

Researchers collected information from 500 children on the amount of violent TV they watched.They also collected ratings of how aggressive these children were.The researchers measured TV watching and aggressiveness when these same subjects more than fifteen years later.The highest correlation was observed between

Accepted Answer

The researchers measured both childhood violent TV watching and adult aggression, and found that there was a correlation between the two. This suggests that childhood exposure to violent TV may have lasting effects on aggression levels into adulthood. The other options either do not account for both childhood and adult measurements, or do not show the same correlation as C.

Question 8

The main ethical principle guiding psychology experiments with human participants is

Accepted Answer

The main ethical principle guiding psychology experiments with human participants is informed consent, which means that participants must be fully informed about the procedures and risks involved in the experiment and must provide their voluntary agreement to participate. This principle ensures that participants are treated with respect and dignity and that their autonomy is respected. Choices A, C, and D do not accurately reflect ethical principles in psychology research. Repeating an experiment is common practice in scientific research to ensure the validity of findings, compensation may be offered but is not a guiding principle, and telling participants the theory behind the research is not sufficient for obtaining informed consent.

Question 9

To test the value of the study guide,Professor Lewis gives a free copy to the students sitting in the first two rows of class.Later she finds that these students got better grades than the students in the back of the room (who didn't get study guides).What is wrong with this experiment?

Accepted Answer

The experiment lacks random assignment to groups, which means that there may be other factors influencing the results and not solely the study guide. The students in the first two rows may have been better prepared or more motivated to study than those in the back of the room, which confounds the results. Therefore, this experiment cannot establish a cause-and-effect relationship between the study guide and the improved grades, and it cannot be used to generalize to the larger population.

Question 10

To test the effect of an informal atmosphere on class performance,Professor Hall dresses in shorts and bare feet for his morning class and in conventional clothing for his afternoon class.He then counts the number of "intelligent questions" in each class and reports more in the class for which he wore shorts.What are the two things wrong with this experiment?

Accepted Answer

The experiment lacks random assignment because students are not randomly assigned to the morning or afternoon class, which could introduce confounding variables related to the time of day. Additionally, the observations are not blind; Professor Hall knows which condition he is observing, which could bias his assessment of what constitutes an "intelligent question."

Question 11

An experimenter tests the reading skills of some 10-year-old children,puts them on a low-fat diet for 6 months,retests their reading skills,and finds that most show a significant improvement in their reading.The experimenter concludes that a low-fat diet improves intellectual development.One major defect in this study is the lack of any

Accepted Answer

The lack of a control group makes it impossible to determine whether the improvement in reading skills was due to the low-fat diet or some other factors. Without a control group, the experimenter cannot rule out alternative explanations for the observed effect.

Question 12

Which cause-and-effect conclusion,if any,can we draw from the correlational studies of watching violent television?

Accepted Answer

Correlational studies can only show a relationship between two variables, but they cannot prove causation. Therefore, we cannot draw any cause-and-effect conclusions from correlational studies of watching violent television.

Question 13

The control group in an experiment is a group that

Accepted Answer

The control group is a comparison group that is treated the same as the experimental group except for the treatment that the experiment is designed to test. This allows for a comparison to be made between the two groups and helps to ensure that any differences observed are due to the treatment and not some other factor.

Question 14

In one study,the experimental group is subjected to loud,unpredictable noises to see whether or not those noises will affect performance on a memory task.What will the control group do?

Accepted Answer

The control group should perform the memory task without the unpredictable noises, as this will serve as a baseline for comparison to the experimental group's performance. This allows researchers to determine if any differences in performance between the two groups can be attributed to the effects of the unpredictable noises.

Question 15

Random assignment is a procedure that psychological researchers apply to their

Accepted Answer

Random assignment is the process of randomly assigning participants to different groups or conditions in a research study. Therefore, it pertains to selecting participants.

Question 16

To test the effects of eating on learning,Professor Lee permits her morning class to bring snacks to class but forbids her afternoon class from bringing snacks.To measure performance,she counts the number of "intelligent questions" asked by students in each class,and reports getting more such questions in the morning class.What are two serious flaws in this experiment?

Accepted Answer

The two serious flaws in this experiment are lack of random assignment and lack of blind observations. Random assignment helps ensure that any differences in performance between the morning and afternoon class are not due to pre-existing differences between the students in those classes. Blind observations would prevent the experimenter from being biased in counting the number of "intelligent questions" asked by the students, as they may unconsciously count more in the morning class because of their belief that eating snacks improves performance.

Question 17

Which of the following is the BEST conclusion from the research discussed on the effects of watching television violence and aggressive behavior?

Accepted Answer

The research discussed in the question suggests that both experiments and correlational studies show a positive association between viewing violence and greater aggressiveness. Therefore, the best conclusion from this research is that viewing violence is associated with greater aggressiveness, as supported by both types of studies.

Question 18

The experimental group in one study receives a free copy of the study guide so that the experimenter can determine the effect of the study guide on test performance.What will the control group in this experiment do?

Accepted Answer

The control group in an experiment serves as a baseline and allows the experimenter to compare the results of the experimental group to those of a group that did not receive the intervention (in this case, the study guide). In order for the comparison to be valid, the control group must take the same tests as the experimental group without using the study guide. This allows the experimenter to determine if the study guide had an effect on test performance. Therefore, option B is the best choice. The other options do not accurately describe the purpose or function of the control group in this experiment.

Question 19

Random assignment is

Accepted Answer

Random assignment is the process of randomly assigning participants to either the experimental or control group in order to minimize the effects of confounding variables. This helps ensure that differences in the outcome are due to the independent variable being manipulated and not due to other factors. Therefore, choice A is the correct answer because it accurately describes random assignment.

Question 20

To examine the value of looking at old tests,Professor King hands out copies of old tests to the first 20 students who come to class one day.Later she finds that these students got better grades than the other students in the class.What is wrong with this experiment?

Accepted Answer

The experiment lacks random assignment to groups, meaning that the 20 students who received old tests may have had some advantage over the other students in the class. It is possible that they were simply better prepared or more interested in the material, rather than the old tests themselves having any value.

Quiz 2: Scientific Methods in Psychology