ap psych ch2

confounding variables

confounding variables

unwanted influence on the outcome of an emperiment

experiment

researcher controlls all conditions and manipulates independent variable

replicate

doing a study again 2 see if same results are obtained

dependent variable

measured outcome and response of the subjects in a study

data

information gathered by researcher

random presentation

chance alone determines the order in which stimulus is presented

independent variable

stimulus changes the experiment independently of all conditions

operational definitions

descriptions of conditions of a scientific study

hypothesis

predicting the outcome of a scientific study

theory

testable explanations for a set of facts

empirical investigation

approach to research that relies on observations and research

scientific method

a five-step process for empirical investigation that controls biases

correlation

changes in one variable reflect changes in other

correlation coefficient

number between -1 and +1 representing relationship between two variables

inferential statistics

used 2 see if results are reliable or by chance

random sample

sample group w/subjects selected by chance

representative sample

sample reflects important variables in the larger pop.

significant difference

difference between the “real” when probability might be due to atypical sample

normal distribution

spread of characteristic throughout a population

standard deviation

indicates average difference between the scores and their mean

range

difference between the highest and lowest values

mode

score that occurs more often than any other

median

score that separates the upper half of the scores in a distribution from lower half

mean

adding all scores and dividing by number of scores

descriptive statistics

describes characteristics and responses of groups of subjects

histogram

bar graph depicting a frequency distribution

frequency distribution

chart that shows how frequently each scores occur in data

double-blind study

both subjects that research/participate are uninformed abt the independent variable

expectancy bias

researcher allows his/her expectations to affect outcome

personal bias

personal beliefs affect outcome of study

cohort sequential study

a study where cross section of the pop. is chosen and then each cohort is followed for a short period of time

cross-sectional study

a study where cross section of the pop. is tested at one specific time

longitudinal study

a study where a group of subjects is followed and observed for years

naturalistic observation

subjects are observed in natural environment

survey

set of questions are asked to subjects

correlation study

study that determines the relationship between two variables

ex post facto

subjects chosen based on pre-existing condition facto

random assignment

subjects have equal likelyhood of being chosen for an assignment

controls

constraints that ensure subjects have same conditions

institutional review board

a committe where research is conducted to every experiment for ethics

institutional animal care and use committe

a committe where research is conducted to review every experiment involving animals for ethics