sample
(noun)Definition of sample
A subset of a population selected for measurement, observation or questioning, to provide statistical information about the population.
Source: Wiktionary  CC BYSA 3.0
Examples of sample in the following topics:

Defining the Sample and Collecting Data
 For example, a researcher concerned with drawing a statistical generalization across an entire population may administer a survey questionnaire to a representative sample population.
 The stages of the sampling process are defining the population of interest, specifying the sampling frame, determining the sampling method and sample size, and sampling and data collecting.
 A probability sampling is one in which every unit in the population has a chance (greater than zero) of being selected in the sample, and this probability can be accurately determined.
 Sampling errors and biases, such as selection bias and random sampling error, are induced by the sample design.
 Nonsampling errors are other errors which can impact the results, caused by problems in data collection, processing, or sample design.
 Defining the sample and collecting data are key parts of empirical research, whether the observations will be statistical or ethnographic.

Surveys
 In order for the results of a survey to be valid, the sample used has to be both random and representative.
 Typically this is obtained via a stratified random sample.
 A stratified random sample is a subset of the population that is drawn in such a way that every member of the population and important subcategories of the population have an equal chance of being selected for the survey, yielding a sample that is demographically similar to the population.
 A convenience sample is not considered rigorous or accurate—it results in a nonrepresentative sample.
 Generalizability means that the results from the sample can be assumed to apply to the general population with confidence.

Preparing the Research Report
 In the methodology section, be sure to include: the population, sample frame, sample method, sample size, data collection method, and data processing and analysis.

Nature Versus Nurture: A False Debate
 However, sample sizes are usually small, so generalization of the results must be done with caution.

Microfinancing
 In 2006, in a sample of 704 microfinance institutions that voluntarily submitted reports to the MicroBanking Bulletin, the real average portfolio yield was 22.3% annually.

Social Control Theory
 Nye conducted formal interviews of 780 young people in Washington State, though his sample was criticized for not including individuals from urban backgrounds and for only selecting individuals who were likely to describe their families unfavorably.

The Power of Authority: The Milgram Experiment
 The teacher was given an electric shock from the electroshock generator as a sample of the shock that the "learner" would supposedly receive during the experiment.

Sexual Behavior: Kinsey's Study
 Among Kinsey’s sample, 26% of females had extramarital sex by their forties.