Define:

scientific method

general procedures psychologists use for gathering and interpreting data

Define theory as it relates to research methods.

organized, testable explanation of phenomena

Other researchers must be able to __replicate__ the results of an experiment to validate its conclusions.

What is replication?

obtaining similar results to a previous study using the same methods

What is hindsight bias?

The tendency of people to overestimate their ability to predict an event after it happened.

What is a controlled experiment?

researchers systematically manipulate a variable and observe the response in a laboratory

Define:

hypothesis

prediction of how two or more factors are related

What is the difference between an independent variable and a dependent variable in an experiment?

The factor being manipulated is the **independent** variable. The factor being measured is the **dependent** variable.

Identify the independent and dependent variables:

If students use Brainscape to study, rather than simple flash cards, then they will get higher test scores.

**independent:**method of studying**dependent:**test score

Define population as it relates to research methods.

all the individuals to which the study applies

Define sample as it relates to research methods.

subgroup of a population that constitutes participants of a study

What type of sample should be used in research?

Larger sample sizes are ideal because they are the most representative of the population.

The amount of difference between the sample and population is called __________.

sampling error

Define random selection as it relates to research methods.

every individual from a population has an equal chance of being chosen for the sample

Which individuals are in the experimental group?

subjects who receive the treatment or manipulation of the independent variable

Which individuals are in the control group?

subjects who do not receive any treatment or manipulation

Subjects who receive the treatment are part of the __________, while those who do not receive the treatment belong to the __________.

experimental group; control group

What type of experimental design uses experimental and control groups?

A match pair between subjects uses an experimental group and a control group to compare the effect of the independent variable.

What process is used to ensure there are no preexisting differences between the control group and the experimental group?

Random assignment fairly divides the sample participants into the two groups.

Define:

confounding variable

- any difference between the experimental group and the control group, besides the effect of the independent variable
- a.k.a. third variable

List four types of confounding variables.

- experimenter bias
- demand characteristics
- placebo effect
- lack of counterbalancing

Define experimenter bias as it relates to confounding variables.

Experimenter bias occurs when a researcher’s expectations or preferences about the results of the study influence the experiment.

Define demand characteristics as they relate to confounding variables.

clues the participants discover about the intention of the study that alter their responses

Define placebo effect as it relates to confounding variables.

responding to an inactive drug with a change in behavior because the subject believes it contains the active ingredient

Define counterbalancing as it relates to confounding variables.

Researchers using a within-subjects design eliminate the effects of treatment order by assigning half the participants to treatment A first and the other half to treatment B first.

What type of experimental design uses each participant as his/her own control?

A within-subjects design exposes each participant to the treatment and compares their pre-test and post-test results. This design can also compare the results of two different treatments administered.

How do researchers specifically define what variables mean?

Researchers use operational definitions to precisely describe variables in relation to their study. For example, “effectiveness of studying” can be operationally defined with a test score.

What is a single-blind procedure?

research design in which the subjects are unaware if they are in the control or experimental group

What is a double-blind procedure?

research design in which neither the experimenter nor the subjects are aware who is in the control or experimental group

Single-blind procedures aim to eliminate the effects of __________, while double-blind procedures use a third party researcher to omit the effects of __________.

demand characteristics; experimenter bias

What is the Hawthorne effect?

individuals who are being experimented on behave differently than in their everyday life

How are quasi-experiments different from controlled experiments?

Random assignment is not possible in quasi-experiments.

What types of research are considered quasi-experiments?

Differences in behavior between:

- males and females
- various age groups
- students in different classes

Define:

correlational research

- establishes a relationship between two variables
- does not determine cause and effect
- used to make predictions and generate future research

List three types of correlational research.

- naturalistic observation
- surveys
- tests

Define naturalistic observation as it relates to correlational research.

Naturalistic observation consists of field observation of naturally occurring behavior, such as the way students behave in the classroom. There is no manipulation of variables.

What are surveys and why are they not always accurate?

- type of correlational research
- questionnaires and interviews given to a large group of people about their thoughts or behavior
- individuals aim to be politically correct and socially accepted, leading them to give false answers

Define tests as they relate to correlational research.

research method that measures individual traits at a specific time and place

__________ studies start by looking at an effect and then attempt to determine the cause.

Ex post facto

What is the difference between the reliability and validity of a test?

A test is **reliable** if it is consistent and repeatable, meaning if you could take the same test a second time, you would get the same result(s)

A test is **valid** if it measures what it is intended to measure. It is often said that a test cannot be valid if it is not reliable.

For example, a bathroom scale is reliable because you can weigh yourself, step off, step back on, then get the same measurement. The bathroom scale is valid for measuring how much you weigh, but invalid for measuring your IQ.

What is a case study?

- detailed examination of one person or a small group
- beneficial for understanding rare and complex phenomena in clinical research
- not always representative of the larger population

What are the strengths and weaknesses of this research method?

experiments

Strengths:

- determine cause and effect relationship between variables
- control over confounding variables

Weaknesses:

- it can be difficult to generalize from the lab to the real world
- expensive
- time-consuming

What are the strengths and weaknesses of this research method?

correlational research

Strengths:

- easy to administer surveys or tests
- inexpensive
- minimal time needed
- substantial real-world generalizability

Weaknesses:

- no control over confounding variables
- skewed or biased results
- establishes a relationship, not causation

Define:

statistics

analysis of numerical data regarding representative samples

__________ data includes numerical measurements and __________ data includes descriptive words.

Quantitative; qualitative

What are the four scales of measurement?

- nominal
- ordinal
- interval
- ratio

Define:

nominal scale

numbers have no meaning except as labels

Example: Girls are designated as 1 and boys are designated as 2.

Define:

ordinal scale

numbers are used as ranks

Example: The highest score is designated as 1, second highest as 2, third highest as 3, and so on.

Define:

interval scale

numbers that have a meaningful difference between them

Example: Temperature: The difference between 10°F and 20°F is the same as between 30°F and 40°F.

Define:

ratio scale

numbers that have a meaningful ratio between them on a scale with a real zero point

Example: Weight and height: If you weight zero pounds, you have no weight. 100 pounds is twice as heavy as 50 pounds.

Would temperature be measured on an interval scale or a ratio scale?

interval

If the temperature is 0°F, there is not “no temperature.” There is not a meaningful ratio between values. 100°F is not twice as hot as 50°F.

What are descriptive statistics?

numbers that summarize a set of research data from a sample

Define:

frequency distribution

an orderly arrangement of scores indicating the frequency of each score

What is the difference between a histogram and a frequency polygon?

A **histogram** is a bar graph and a **frequency polygon** is a line graph or a bell curve.

Define and list the three types of:

central tendency

Measures of central tendency describe the most typical scores for a set of research data.

- mode
- median
- mean

Define in terms of central tendency:

mode

most frequently occurring score in the data set

Define in terms of central tendency:

median

the middle score when the data is ordered by size

Define in terms of central tendency:

mean

arithmetic average of the scores in the data set

If two scores appear most frequently, the distribution is __________, and if there are three or more appearing most frequently, it is __________.

bimodal; multimodal

Which measure of central tendency is the most representative? The least representative?

- mean is usually most representative, unless there are extreme outliers that pull the mean in a particular direction
- median is less sensitive to outliers, but is a weak statistic
- mode is the least representative

Define:

normal distribution

bell-shaped, symmetric curve that represents data about many human characteristics throughout the population

When most of the scores are compacted on one side of the bell curve, the distribution is said to be __________.

skewed

Positively skewed distributions include a lot of small values and negatively skewed distributions include a lot of large values.

Define and list the three types of:

measures of variablity

Measures of variability describe the dispersion of scores for a set of research data.

- range
- variance
- standard deviation

Define in terms of variability:

range

difference between the largest score and the smallest score

What do variance and standard deviation measure?

average difference between each score and the mean of the data set

Taller, narrow curves have less variance than short, wider curves.

What is a *z* score (a.k.a. standard score)?

- allows for comparison between different scales
- subtract mean from each score and divide by standard deviation
- mean has a z score of zero

Define:

percentile score

percentage of scores at or below a particular score between 1 and 99

Example: If you are in the 70th percentile, 70% of the scores are the same as or below yours.

Define:

Pearson correlation coefficient

- statistical linear measure of the relationship between two sets of data
- varies from -1 to +1
- helps to make predictions about variables

Name the correlation coefficient for each and describe the relationship:

- perfect positive correlation
- no relationship
- perfect negative correlation

- r = +1
**direct relationship:**as one variable increases or decreases, the other does the same - r = 0

no relationship - r = -1
**inverse relationship:**as one variable increases or decreases, the other does the opposite

What type of graph plots single points to show the strength and direction of correlations?

scatterplot

What is the term for the line on a scatterplot that follows the trend of the points?

line of best fit or regression line

Define:

inferential statistics

- used to interpret data and draw conclusions
- indicate generalizability to population
- indicate real relationship, not due to chance

What is the difference between a null and an alternative hypothesis?

**Null** hypotheses state that a treatment had no effect, while **alternative** hypotheses state the treatment did have an effect in the experiment.

What is the difference between a Type I and Type II error?

**Type I** errors, or false positives, occur if the researcher rejects a true null hypothesis. **Type II** errors, or false negatives, occur if the researcher fails to reject a false null hypothesis.

The variable *p* represents __________.

statistical significance

When is a finding statistically significant?

when the probability (alpha) that the finding is due to chance is less than 1 in 20 (p < 0.05)

Said another way, when you are 95% confident that the result was not due to chance

What method statistically combines the results of several research studies to reach a conclusion?

meta-analysis

Why did the American Psychological Association (APA) implement ethical guidelines?

- Guidelines were set in place in the late 20th century to stress responsibility and morality in research and clinical practice
- Dangerous and inhumane experiments such as Harlow’s rhesus monkeys, Zimbardo’s prison role-playing, and Milgram’s shock test led to the implementation of rules

What are the purposes of an Institutional Review Board (IRB)?

- approve research being conducted at their particular institution
- require participants give informed consent after hearing the risks and procedures
- require debriefing of participants afterward with results of research
- ensure humane and ethical treatment of animal and human subjects

__________ psychology is practical and designed for real world application, while __________ psychology is focused on research of fundamental principles and theories.

Applied; basic