AP Psychology: Unit 2 Research Methods

operational definitions

a researcher's explanation how the variable of an experiment will be measured

valid

research that measures what the researcher set out to measure; accurate

reliable

research that can be replicated and is consistent

participants

individuals on which research is conducted

sampling

the process by which participants for research are selected

population

includes anyone or anything that could possibly be selected to be in the sample for research

random selection

every member of the population has an equal chance of being selected as a participant in research

confounding variables

any difference between the experimental and control conditions, except for the independent variable, that might affect the dependent variable

assignment

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

random assignment

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

participant-relevant confounding variables

when groups are not randomly assigned during an experiment; increases the chance of participants in the two groups differ in any meaningful way

situation-relevant confounding variables

when the situations into which the different groups of an experiment are put are not truly equivalent; can create invalid experiment results due to the situation rather than the independent variable

experimenter bias

the unconscious tendency for researchers to treat members of the experimental and control groups differently to increase the chance of confirming their hypothesis

double-blind procedure

when neither the participants nor the researcher are able to affect the outcome of the research

response bias

the tendency for subjects to behave in certain ways; can alter validity of experiment

confirmation bias

the tendency to attend to evidence that complements and confirms our beliefs or expectations, while ignoring evidence that does not

scientific method

developing a hypothesis, performing a controlled test, gathering objective data, analyzing results, and publishing, criticizing, and replicating the results

correlational studies

non-experimental method; a type of research that is mainly statistical in nature; determines the relationship between two variables

survey

non-experimental method; a quasi-experimental method in which questions are asked to subjects; when being designed, the researcher hast o be careful that the questions are not skewed or biased towards a particular answer

naturalistic observation

non-experimental method; research in which subjects are observed in their natural environment

longitudinal study

non-experimental method; a type of study in which one group of subjects is followed and observed (or examined, surveyed, etc.) for an extended period of time (years.)

cross-sectional study

a study in which a representative cross section of the population is tested or surveyed at one specific time

frequency distribution

a summary chart, showing how frequently each of the various scores in a set of data occurs

histogram

a bar graph depicting a frequency distribution; the height of the bars indicates the frequency of the group of scores

descriptive statistics

statistical procedures used to describe characteristics and responses of groups of subjects

measure of variability

how closely scores bunch up around the central point; a statistic that indicates the spread of distribution

measures of central tendency

averages; mean, median, and mode

hindsight bias

people's tendency upon hearing about research findings to think that they knew it all along

applied research

research conducted in order to solve practical problems

standard deviation

a measure of variability that indicates the average difference between the sources and their mean

normal distribution

a bell-shaped curve, describing the spread of a characteristic throughout a population

correlation coefficient

a number between -1 and +1 expressing the degree of relationship between two variables

inferential statistics

statistical techniques (based on probability theory) used to assess whether the results of a study are reliable or whether they might be simply the result of chance; often used to determine whether two or more groups are essentially the same or different

representative sample

a sample obtained in such a way that it reflects the distribution of important variables in the larger population in which the researchers are interested; variables such as age, income level, ethnicity, and geographic distribution

basic research

explores questions that are of interest to psychologists but are not intended to have immediate, real-world applications; also referred to as experimental psychology