Chapter 2 Barron's AP Psychology

frequency distribution

a distribution of observed frequencies of occurrence of the values of a variable

case study

a full, detailed picture of one subject or a small group of subjects; not reflective of population, as a result findings cannot be generalized

hypothesis

a relationship between two variables

correlation

a relationship between two variables without ascribing cause

scatter plot

a series of points plotted on a graph the closer the points come to a line, the stronger the correlation

theory

an explanation of some phenomenon, allows researchers to generate testable hypotheses

confounding variable

any difference between the experimental and control conditions, besides the changes of the independent variable

population

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

measures of variability

attempt to depict the diversity of the distribution consists of range, variance, standard deviation compare: measures of central tendency

measures of central tendency

attempt to mark the center of a distribution consists of mean, median, mode compare: measures of variability

histogram

bar graph

anonymity/confidentiality

both protect privacy anonymity- no data that allows researchers to match the data with the person confidentiality- the source of any data will not be revealed

reliable

can be replicated, consistent compare: valid

laboratory experiment

conducted in a lab, a highly controlled environment

field experiment

conducted in the world, more realistic than laboratory experiment compare: laboratory experiment

demand characteristics

cues about the purpose of the study

dependent variable

depends on the independent variable

descriptive statistics

describe a set of data compare: inferential statistics

inferential statistics

determine whether or not findings can be applied to the larger population from which the sample was selected; making sure the results are not due to sampling error and chance t-tests, ANOVAs, MANOVAs are types of inferential statistical tests compare: descriptive statistics

situation-relevant confounding variables

differences between the experimental and control situations that may affect the experiment equivalent environments control for situation-relevant confounding variables

random assignment

each subject has an equal chance of being placed in either the experimental or the control group controls subject-relevant confounding variables compare: random selection

sample

group of subjects; should be representative of a larger population

group matching

half of each condition (for example, male or female) is assigned to each group (experimental or control) compare: stratified sampling

survey method

kind of correlational research in which surveys are filled out; difficult to control for confounding variables

frequency polygon

line graph

valid

measures what it's supposed to measure; accurate compare: reliable

double-blind procedure

neither the subjects nor the researcher are able to affect the outcome of the research minimizes the effect of demand characteristics and some kind of response/subject bias compare: single-blind procedure

experiment

only experiments can show cause and effect relationships through the manipulation of the independent variable and subsequent observation of the dependent variable while controlling for confounding variables

single-blind procedure

only the subjects do not know which group they're in minimizes the effect of demand characteristics and some kind of response/subject bias compare: double-blind procedure

risk

participants cannot be placed in significant mental or physical risk

debriefing procedures

participants must be told the purpose of the study and provided with ways to contact the researchers about study results

informed consent

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

coercion

participation must be voluntary

stratified sampling

randomly sampling each strata (category of people, for example race or gender) of the population, so that the final sample reflects the population more accurately

random selection

randomly selecting the sample group, increases the likelihood that the sample represents the population

correlation coefficient

range from -1 and +1 0 is the weakest correlation-- no correlation

ex post facto study

research in which subjects are chosen based on a pre-existing condition; all other variables are controlled

basic research

research that explores questions that are of interest of psychologists that are not intended to have immediate, real-world applications compare: applied research

applied research

research with clear, practical applications compare: basic research

institutional review board

reviews research proposal for ethical violations and/or procedural errors

Hawthorne effect

selecting a group of people on whom to experiment will affect the performance of hat group, regardless of what is done to the individuals

mean

the average of all the scores in a distribution most commonly used measure of central tendency when distorted by extreme scores or outliers, median should be used compare: median, mode

variance

the average of the squared differences of each number from the mean compare: standard deviation, range

range

the distance between the highest and lowest score in a distribution compare: variance, standard deviation

percentile

the distance of a score from 0 nth percentile means you scored better than n percent of the people taking the test

z score

the distance of a score from the mean in units of standard deviation negative z scores are below the mean positive z scores and above the mean

sampling error

the extent to which a sample differs from the population

line of best fit

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

median

the middle score of a distribution when written in ascending or descending order compare: mode, mean

order effect

the order of the experimental/control group activities may affect the results

subjects

the participants in research

p value

the percent chance that the findings were due to chance .05 (5% chance) is the cut off for statistically significant results p value of 0 cannot exist

assignment

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

sampling

the process by which subjects are selected

placebo effect

the purely psychological effects of thinking you took a drug when you really didn't

mode

the score that appears most frequently compare: median, mean

standard deviation

the square root of the variance compare: variance, range

experimenter bias

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

normal curve

theoretical bell-shaped curve for which the area under the curve lying between any two z scores has been predetermined memorize the normal distribution chart

variables

things that vary among the participants in the research

operationalize

to explain how you will measure a variable

naturalistic observation

unobtrusive observation on subjects in their natural habitats, control is sacrificed compare: field experiment

counterbalancing

using subjects as their own control group by having half of them be experimental first and half of them be control first

positively skewed

when a distribution has a high outlier, there are more low scores than high scores due to the outlier mean is higher than median compare: negatively skewed

negatively skewed

when a distribution has a low outlier, there are more high scores than low scores due to the outlier mean is lower than median compare: positively skewed

response/subject bias

when subjects behave in ways they think the observer wants them to behave social desirability (desire to act or answer questions in a way that others will like) is a type of this