Chapter 2: Psychological Research

Population

Population

broad group researcher is interested in ex: autistic children

ex: adolescents in the U.S.

Sample

(i.e., participants) subset chosen to represent population

ex: because you can't measure every autistic child

representative sample

subset of the population that accurately represents the general population

correlational study

a research project designed to discover the degree to which two variables are related to each other

advantages: real world

disadvantages: can’t determine causes

Experimental study

the researcher manipulates one of the variables and tries to determine how the manipulation influences other variables

advantages: isolates causes

disadvantages: can be artificial; sometimes can't be done

positively correlated

describes two series that move in the same direction

negatively correlated

describes two series that move in opposite directions

correlation coefficient

It means one variable increases, the other decreases(-+)

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

depentent variable

the factor that may change in response to the independent variable, the item that you measure.

understand importance of random assignment in an experimental study

Each participant has same probability as any other of being assigned to a given group. Previous Example of study hours & grades: Random assignment would ensure all the high IQ or working people didn't end up in one group

experimenter bias

the influence of the experimenter's expectations on the outcome of research

participant bias

a tendency for research participants to respond in a certain way because they know they are being observed, or they believe they know what the researcher wants

placebo & what it's used for

people's expectations or beliefs influencing or determining their experience in a given situation and to improve real mental processes on the body(relaxation response or distraction on from pain, itching, a conditioned response, etc.)

What is a double-blind procedure and why is it used?

experiment in which both the researchers and the participants are blind to group assignments