Term

Definition
We observe individuals and measure variables of interest but do not attempt to influence the responses. 


Term

Definition
We deliberately impose some treatment on individuals in order to observe their responses. 


Term

Definition
The entire group of individuals that we want information about. 


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Definition
The part of the population that we actually examine in order to gather information. 


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Definition
Studying a part in order to gain information about the whole. 


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Definition
Attempts to contact every individual in the entire population. 


Term
Voluntary Response Sample 

Definition
Consists of people who choose themselves by responding to a general appeal; tend to be biased because people with strong opinions, especially negative opinions, are most likely to respond. 


Term

Definition
Choosing individuals who are easiest to reach. 


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Definition
A sampling method that systematically favors certain outcomes. 


Term
Simple Random Sample (SRS) 

Definition
Size n consists of n individuals from the population chosen in such a way that every set of n individuals has an equal chance to be the sample actually selected. 


Term

Definition
A long string of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 with each entry in the table equally likely to be any of the 10 digits and the entries are independent of each other. 


Term

Definition
The general framework for a method that uses chance to choose a sample. 


Term

Definition
A sample chosen by chance; we must know what samples are possible and what chance, or probability, each possible sample has. 


Term

Definition
The population is divided into groups of individuals, called strata, that are similar in some way that is important to the response. 


Term

Definition
Divides the population into groups, or clusters. Some of these clusters are randomly selected. Then all individuals in the chosen cluster are selected to be in the sample. 


Term

Definition
Occurs when some groups in the population are left out of the process of choosing the sample. 


Term

Definition
Occurs when an individual chosen for the sample can't be contact or does not cooperate. 


Term

Definition
The behavior of the respondent or of the interviewer that can bias an answer. 

