Question 1

Two primary considerations in psychological measurement are validity and reliability. Without both, the results of a psychological study are meaningless. Explain the concepts of validity and reliability.

Accepted Answer

The answer should provide the following information: (1) Validity refers to the extent to which a measurement and a property are conceptually related. A valid measure is one that measures what it claims to measure; in other words, the operational definition of a property must overlap with the conceptual definition of that property. A researcher using invalid measures is claiming to measure one thing, but is instead measuring something else; (2) Reliability refers to the consistency of a measurement. A reliable measure gives the same kind of results each time it is used. So, for example, a reliable measure of intelligence would yield the same kinds of test results each time it is administered, just as a reliable 12-inch ruler would measure 12 inches no matter who was holding it. A researcher using unreliable measures has no basis for knowing that the measurements taken reflect aspects of the property to be measured.

Question 2

What is the third-variable problem, and how does it relate to correlational research in psychology? Give examples.

Accepted Answer

The answer should indicate that the third-variable problem is the fact that two variables may be correlated only because they are both caused by a third variable. The third-variable problem is encountered often in observations of natural correlations. Because of the third-variable problem, just because two variables are correlated does not necessarily mean that one is causing the other to occur. The third-variable problem always exists in correlation studies; no matter how much we control for relevant third variables, another always exists. An example of the third variable problem involves the correlation between watching violent television programming and childhood aggression. From this correlation alone, we cannot say that watching violent television programming causes aggression. It may be that a third variable-lack of parental supervision-causes both television viewing and aggression.

Question 3

Generate your own unique example of an experiment. First, generate a hypothesis. Next, state the independent and dependent variables. Also, specify how participants will be assigned to the treatment and control groups.

Accepted Answer

The answer should provide the following information: Example: To find out if the drug Trimjeans really facilitated weight loss, researchers, in a double-blind experiment, gave a placebo to half the randomly selected participants and the drug Trimjeans to the other half of the participants. After a trial period of taking one pill per day for 3 months, the weights of the participants were studied. Participants were weighed every day. The independent variable was the drug Trimjeans because it was the variable being manipulated. The dependent variable was the participants' weights because it was what was being measured. The experimental group was the half that received the drug, and the control group was the placebo group.

Question 4

Describe the major reason that causation cannot be derived from a correlation and at least two ways to try to control the problem.

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Question 5

A psychologist theorizes that depression is caused by low levels of the neurotransmitter serotonin in the brain. Generate a hypothesis based on this theory.

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Question 6

Explain the difference between a population and a sample. Then, discuss the relationship between random sampling and generalizing findings from the sample to the population.

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Question 7

What are demand characteristics? Give at least three examples of how to control demand characteristics.

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Question 8

A true experiment is defined as having certain characteristics. Deconstruct an experiment into its two essential characteristics, and note how each helps to achieve the overall goal of internal validity.

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Question 9

Generate your own example of a measure that is (a) reliable but not valid, and (b) neither reliable nor valid.

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Question 10

Although psychologists and chemists both use the scientific method, discuss three reasons why the subject matter of psychology is much more difficult to study than the subject matter of chemistry.

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Question 11

Self-help guru, Louise Hay, claims that her self-help DVDs can cure cancer. Describe how you would design an experiment to test this claim. To get you started, suppose that the participants in the experiment are individuals recently diagnosed with cancer who have provided informed consent to participate in a study investigating the power of positive thinking. From here, describe how you would use random assignment and manipulation to test Hay's claim. Be sure to identify the independent and dependent variables.

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Question 12

Contrast how a dogmatist and an empiricist might react to the statement that drug addiction is a "disease of the brain."

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Question 13

List at least three rules of ethics that psychologists must follow to maintain the safety, well-being, and dignity of their participants.

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Question 14

According to Sir Francis Bacon, what two human tendencies interfere with our ability to think critically? Provide examples of each.

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Question 15

Define internal and external validity, and give an example illustrating each.

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Question 16

Develop an operational definition that could be used to measure the terms happiness and shyness.

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Exam 2: Section 1: Methods in Psychology