group of individuals of the same species that live in the same area
A characteristic or measure of a population.
The original data as it was collected from a sample.
a subset of the population
a numerical measure that describes an aspect of a sample
margin of error
Confidence Interval (CI)
Given a sample from a population, the CI indicates a range in which the population mean is believed to be found. Usually expressed as a 95% CI, indicating the lower and upper boundaries. (sample statistic -+margin of error)
a sample that is not representative of the population
a sample in which every element in the population has an equal chance of being selected
simple random sampling
a probability sampling procedure in which every sampling unit has a known and equal chance of being selected
A complete enumeration of a population.
a sample that accurately reflects the characteristics of the population as a whole
Every nth item in the target population is selected
a form of nonprobability sample using respondents who are convenient or readily accessible to the researcher�for example, employees, friends, or relatives
An economically efficient sampling technique in which the primary sampling unit is not the individual element in the population but a large cluster of elements, clusters are selected randomly
A type of probability sampling in which the population is divided into groups with a common attribute and a random sample is chosen within each group
research that gathers data in a real-world setting without intentionally manipulating any variable
gathering primary data by selecting matched groups of subjects, giving them different treatments, controlling related factors, and checking for differences in group responses
people on whom we experiment
variables of interest
the items or quantities that the study seeks to measure
a variable that we think explains or causes changes in the response variable
a variable that measures an outcome or result of a study
an observational study in which subjects are selected and then their previous conditions or behaviors are determined
prospective study(longitudinal study)
an observational study in which subjects are followed to observe future outcomes
the group that receives the treatment
In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.
Occurs when factor is related to both exposure and outcome, but is not the the causal pathway; factor distorts or confuses effect of the exposure on outcome
a factor other than the independent variable that might produce an effect in an experiment
the phenomenon in which the expectations of the participants in a study can influence their behavior
something which has a positive mental effect, but no physical effect
a threat to internal validity in which the experimenter, consciously or unconsciously, affects the results of the study
study in which the subjects do not know if they are in the experimental or the control group
An experiment in which neither the participant nor the researcher knows whether the participant has received the treatment or the placebo
any individual associated with an experiment who is not aware of how subjects have been allocated to treatment groups
Combined results from numerous studies to assess the effect of common variables
A process by which the procedures and results of an experiment are evaluated by other scientists who are in the same field or who are conducting similar research.
A polling error in which the sample is not representative of the population being studied, so that some opinions are over- or underrepresented
occurs any time participation in a study is voluntary
is one in which the respondents themselves decide whether to be included
Collection of methods for planning experiments, obtaining data, organizing, summarizing, presenting, analyzing, interpreting, and drawing conclusions based on data.