Psychology Unit 0

experiment

a study that tries to answer the question of causality

hypothesis

an informed guess about the results of a study

operational definitions

the way that a study will measure or observe certain variables

population

the type of people a study can say something about

sample

the participants included in our study from the population

random sampling

the random selection of participants included in a study from the population

convenience sampling

the selection of participants that are easiest to include

independent variable (IV)

the variables a researcher manipulates/changes

dependent variable (DV)

the variable a researcher measures

extraneous/confounding variables

the variables that can influence the dependent variable and acts like an independent variable

experimental group (EG)

the group of participants that receives the independent variable

control group (CG)

the group of participants that does not receive the independent variable

random assignment

the random assorting of participants into the control or experimental group

sampling bias

the way that certain groups of people may be overcompensated in an example

placebo effect

the way that a brief about the effectiveness of a fake independent variable may make it look like a real independent variable

social desirability bias

the way that participants may alter their responses in order to appear more socially acceptable

halo effect

the way that the perception of one attractive trait bleeds into the assumption of more attractive traits

experimenter bias

the way that the researchers beliefs about the hypothesis may lead the results to appear confirmed

sing-blind procedure

when participants don’t know if they are receiving the independent variable

double-blind procedure

when neither the participants nor the researcher know if the participant is receiving the independent variable

peer review

before publication of a study, experts in the same field will evaluate the study to determine it’s scientific merits

correlational study

a study that focuses on the relationship between two variables and how strong that relationship is

naturalistic observation

researcher observes people in the real world without interference

case studies

in-depth investigation of a single individual (used for rare diagnosis and unusual data)

longitudinal study

studies the same feature(s) in the same participants over the course of many years, sometimes decades

cross-sectional study

a snapshot at the same point in time that allows for comparison of participants in different age groups to one another

metal analysis

a statistical method that combines the quantitative results of multiple studies to describe a single effect size

survey

questionnaire or interview that a researcher uses to collect info about participants

quantitative studies

a research method that collects numerical data

qualitative studies

a research method that uses in-depth, narrative data that is not translated into numbers

replication

results should be reproducible by others

mixed method studies

combine qualitative and quantitative studies

falsifiability

the possibility that an idea, hypothesis, or theory can be disproven through observation or experiment

mean

Sum of the scores, divided by the number of scores (“the average”)

mode

The score that occurs with the greatest frequency

median

the middle score after putting the distribution of scores in order

range

the difference between the highest value and the lowest value in a data set (the numerical bounds of the given values)

standard deviation

a statistical measure that qualifies the amount of variation or dispersion in a set of data values

normal distribution (normal curve)

a curve that is symmetric, scores cluster in the center (mean=median=mode), and has no boundaries (line never touches the horizontal axis)

regression toward the mean

the more data that is collected, the more each score is likely to be near the mean

percentile

the number of scores in a distribution that are equal to or below the given individual

statistical significance

a statement that indicates the likelihood that the results were due to chance

p value

a value that indicates the significance of a relationship between two variables

(.05< or equal to is not significant)

(0.5> is significant)

effect size

a measure of the magnitude (or meaningfulness) of a relationship between two variables. measured in cohen’s d

0.0-0.2 → small

0.3-0.5 → medium

0.6-0.9 → large

positive skew

is where the tail points to the positive end

negative skew

is where the tail points to the negative end

psychometrics

are the measures of behaviors and capacities, usually through psych tests. used in personality, intelligence, and diagnostics (SAT, gifted testing)

positive relationship/correlation

as one variable increases, so does the other variable

r value of 0-1

negative relationship/correlation

as one variable increases, the other variable decreases

r value of -1-0

Tuskegee syphilis study

600 black people in Alabama were led to believe they were being treated for syphilis, but were instead left purposefully untreated. sparked the necessity of INFORMED consent.

Stanford prison experiment

a mock prison was opened, to study the effects of a sense of authority, Guards abused their “authority” against prisoners, and the study ended within 6 days (compared to its intended 2 weeks). sparked the necessity of the IRB

Milgram obedience studies

the study made participants “teachers” who “shocked students.” the study wanted to test the ability for participants to stop following harmful commands. sparked the necessity for the IRB to establish morals

debriefing

review methods and aims with participants and check on their wellbeing. now a scientific standard

right to withdraw

ability of participants to leave the study at any time

confidentiality

researchers and participants have right to the results, unless the participant gives permission to share them

confederate

someone who pretends to be a participant but is actually working with the researcher

informed consent

participant must be aware of what the study looks at and what the potential consequences are

informed assent

same as consent, except from minors (who may not have the cognitive abilities to provide legal consent yet)

Internal Review Board (IRB)

Determines what studies are permissible to prevent participant harm

correlation coefficient

is the number that indicates how strong the correlation is (how strong the relationship) (expressed with r)