population
the entire group that is of interest to the researcher
sample
sub set of the population
convenience sampling
sampling technique where subjects are recruited from a nearby source due to convenient accessibility and proximity to researcher
random sampling
sampling technique where population is given equal chance of being selected to be part of the sample
stratified random sampling
sampling technique where population is divided into group and random sampling is done within each group
snowball sampling
sampling technique where individuals of interest are interviewed and they would provide names of others of interest who may consent to being interviewed for the study
experimental method
involves manipulation of IV to see its effects on the DV to establish cause and effect
independent variable
variable manipulated by experimenter to see its effects on another variable
dependent variable
variable measured in response to changes in manipulated variable
experimental group
group of participants subjected to manipulation of IV
control group
group of participants who are not exposed to IV, rather used to provide comparison to the experimental group
controlled variable
variable that remains the same for both experimental and control group throughout the experiment so that the changes observed are the results of the IV
uncontrolled variable
variable that is allowed to stay random as it is predicted to have no effect on the outcome of the experiment
hypothesis
scientific statement based on the available information that can be tested by experimentation
- when appropriate, the statement expresses an expected relationship between IV and DV for the observed phenomena
placebo
dummy pill or harmless substance given as if it were treatment
- used to control participants expectations
variables that can affect changes in DV and outcome in IV
reliability
extent to which the researcher would obtain similar results when the same test is given to the same person again under the same circumstances
types of reliability
validity
extent to which the results of a test reflects what the measurement instrument says it is measuring
types of validity
study design
set of methods and procedures used in collecting and analysing measures of the variables specified in the research problem
cross sectional study design
research design which takes into account age related developmental changes by comparing groups of different ages at the same point in time
longitudinal study design
research design which follows developments of one group over time to look for changes
longitudinal-sequential study design
research design which combines features of both cross sectional and longitudinal design in an attempt to overcome the limitations of each design