Chapter 2: Methods

**hindsight bias**

People have the tendency upon hearing about research findings (and many other things) to think that they knew it all along; this tendency is called

**Basic research**

explores questions that are of interest to psychologists but are not intended to have immediate, real-world applications.

**hypothesis**

expresses a relationship between two variables.

**Variables**

are things that can vary among the participants in the research.

**theory**

aims to explain some phenomenon and allows researchers to generate testable hypotheses with the hope of collecting data that support the theory.

**Operational definitions**

When you operationalize a variable, you explain how you will measure it.

**valid**

when it measures what the researcher set out to measure; it is accurate.

**reliable**

when it can be replicated; it is consistent.

**participants**

The individuals on which the research will be conducted are called

**sampling**

the process by which participants are selected is called

**sample**

(the group of participants)

**random selection**

is that every member of the population has an equal chance of being selected.

**Stratified sampling**

is a process that allows a researcher to ensure that the sample represents the population on some criteria.

**Laboratory experiments**

are conducted in a lab, a highly controlled environment

**field experiments**

are conducted out in the world.

**experiment**

allows the researcher to manipulate the independent variable and control for **confounding variables**.

**Assignment**

is the process by which participants are put into a group, experimental or control.

**Random assignment**

means that each participant has an equal chance of being placed into any group.

**participant-relevant confounding variables**

The benefit of random assignment is that it limits the effect of

**group matching**

If one wanted to ensure that the experimental and control groups were equivalent on some criterion (e.g., sex, IQ scores, age), one could use

**Situation-relevant confounding variables**

can also affect an experiment.

**Experimenter bias**

is a special kind of situation-relevant confounding variable.

**double-blind procedure**

Experimenter bias can be eliminated by using a

**single blind**

occurs when only the participants do not know to which group they have been assigned; this strategy minimizes the effect of **demand characteristics** as well as certain kinds of **response** or **participant bias**.

**social desirability**

One kind of response bias, the tendency to try to give answers that reflect well upon them, is called

**Hawthorne effect**

Merely selecting a group of people on whom to experiment has been determined to affect the performance of that group, regardless of what is done to those individuals.

**placebo effect**

This technique allows researchers to separate the physiological effects of the drug from the psychological effects of people thinking they took a drug

**counterbalancing**

Sometimes using participants as their own control group is possible, a procedure known as

**correlation**

expresses a relationship between two variables without ascribing cause.

**positive correlation**

between two things means that the presence of one thing predicts the presence of the other.

**negative correlation**

means that the presence of one thing predicts the absence of the other.

**survey method**

An even more popular research design is the

**Naturalistic Observation**

The goal of naturalistic observation is to get a realistic and rich picture of the participants’ behavior.

**case study method**

is used to get a full, detailed picture of one participant or a small group of participants.

**Descriptive statistics**

simply describe a set of data.

**frequency polygons**

Frequency distributions can be easily turned into line graphs called

**central tendency**

with at least one group of statistical measures called measures of

**extreme scores** or **outliers**

The mean is the most commonly used measure of central tendency, but its accuracy can be distorted by

**positively skewed**

When a distribution includes an extreme score (or group of scores) that is very high, as in the car example above, the distribution is said to be

**negatively skewed**

When the skew is caused by a particularly low score (or group of scores), the distribution is

**Measures of variability**

are other types of descriptive statistical measures.

***Z*** **scores**

measure the distance of a score from the mean in units of standard deviation.

**percentiles**

indicate the distance of a score from 0.

**correlation**

measures the relationship between two variables.

**correlation coefficient**

The strength of a correlation can be computed by a statistic called the

**scatter plot**

A correlation may be graphed using a

**line of best fit**, or **regression line**

is the line drawn through the scatter plot that minimizes the distance of all the points from the line.

**inferential statistics**

is to determine whether or not findings can be applied to the larger population from which the sample was selected.

**sampling error**

The extent to which the sample differs from the population is known as

**APA Ethical Guidelines**

Any type of academic research must first propose the study to the ethics board or **Institutional Review Board (IRB)** at the institution.

**No coercion**

Participation should be voluntary

**Informed consent**

Participants must know that they are involved in research and give their consent.

**Anonymity or confidentiality**

Participants’ privacy must be protected.

**Risk**

Participants cannot be placed at significant mental or physical risk.

**Debriefing**

After the study, participants should be told the purpose of the study and provided with ways to contact the researchers about the results.