Interactive Psychology - Chapters 1&2

third-variable problem

a correlation observed between two variables is actually explained by the influence of some third variable

mean

a measure of central tendency that is the arithmetic average of a group of scores

median

a measure of central tendency that is the middlemost score; it is obtained by lining up the scores from smallest to largest and identify the middle score

statistical significance

a process that calculates how likely is it that the sample's result (or one even more extreme) came from a population in which there is no relationship

measured variable

a variable that is observed and recorded in some numeric form

manipulated variable

a variable whose levels the researcher controls by assigning different participants to different levels of that variable (used only in experiments)

random sampling

a way of choosing a sample of participants for a study in which participants are selected without bias, for example, by dialing random digits on the telephone (for the sample to generalize to a population)

naturalistic observation

an observational research method in which psychologists observe the behavior of animals and people in their normal, everyday worlds and environments

what are the ten different perspectives for studying psychology?

evolutionary, cultural, cognitive, emotional, biological-neuroscience, developmental, personality, social, psychological, clinical

control group

in an experiment, a group or condition in which some proposed cause is not present

what are the two distinct branches of psychology that developed initially?

scientific & clinical

variability

the extent to which the scores in a batch differ from each other

dependent variable

the measured variable in an experiment (the hypothesized effect)

three criteria for causation

1. covariance 2. temporal precedence 3. no alternative explanations

WEIRD samples include research participants from...

Western, educated, industrialized, rich, and democratic backgrounds

observational research

a descriptive research method in which psychologists measure their variable of interest by observing and recording what people are doing

mode

a measure of central tendency that is the most common score in a batch of scores

random assignment

a procedure used in experimental research in which a random method is used to decide which participants will receive each level of the independent variable

sample

a smaller group of people that participates in the research

false positive

a statistically significant finding that does not reflect a real effect

experimental research

a study in which one variable is manipulated, and the other is measured. experimental research can provide evidence that one variable causes another.

descriptive research

a type of study in which researchers measure one variable at a time, with the goal of describing what is typical

correlational research

a type of study that measures two (or more) variables in the same sample of people, and then observes the relationship between them

standard deviation

a variability statistic that calculates how much, on average, a batch of scores varies around its mean

confound

an alternative explanation for a relationship between two variables; specifically, in an experiment, when two experimental groups accidentally differ on more than just the independent variable, which causes a problem for internal validity

case study

an observational research method in which researchers study one or two individuals in depth, often those who have a unique condition

how to evaluate d values (how far apart two group means are in standard deviation units)

d = .20 (small); d = .50 (medium); d > .80 (large)

effect size

describes the magnitude of the relationship between manipulated or measured variables

steps of the scientific method

focus on a theory -> state a hypothesis -> test with a research method -> analyze the data -> report results -> embark on further inquiry

placebo condition

in an experiment, a group or condition in which people expect to receive a treatment but are exposed only to an inert version, such as a sugar pill

experimental (treatment) group

in an experiment, a group or condition in which some proposed cause is present

what does it mean that "the study of psychology is summative"?

it rests on a body of knowledge that is continuously growing

what can interfere with scientific thinking?

overconfidence effect & confirmation bias

how to evaluate r values (correlation coefficient)

r = .10 (weak); r = .30 (medium); r > .50 (large)

operational definitions

specify the exact process for determining the levels or values of each variable

internal validity

the ability of a study to rule out alternative explanations for a relationship between two variables; one of the criteria for supporting a causal claim

validity

the appropriateness or accuracy of some claim or conclusion

null hypothesis

the assumption that there is truly no relationship between variables in the population

reliability

the degree to which a measure yields consistent results each time it is administered

external validity

the degree to which it is reasonable to generalize from a study's sample to its population of interest

population of interest

the larger set of individuals (or cases) the researcher is trying to understand or describe, such as "New Zealand adults"

independent variable

the manipulated variable in an experiment (the hypothesized cause)

construct validity

the specific assessment of how accurately the operationalizations used in a study capture the variables of interest

theory-data cycle

theory -> hypothesis -> design -> collect data -> compare