chapter 8 Flashcards
What is a population?
the entire group of individuals about which we want information
What is a sample?
a part of the population from which we actually collect information. We use a sample to draw conclusions about the entire population
What is a sampling design?
describes exactly how to choose a sample from the population
What is a sample survey?
A survey conducted on a sample from the population of all individuals about which we desire information. We base conclusions about the population on data from the sample.
What is a convenience sample?
a sample composed of members of the population who are selected by the researcher because they are easy to reach.
What is bias?
The design of a statistical study is biased if it systematically favors certain outcomes.
What is a voluntary response sample?
consists of people who choose themselves by responding to a broad appeal. Voluntary response samples are biased because people with strong opinions are most likely to respond.
What is a simple random sample?
of 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.
What is a table of random digits?
a long string of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 with these two properties:
1. Each entry in the table is equally likely to be any of the 10 digits 0 through 9.
2. The entries are independent of each other. That is, knowledge of one part of the table gives no information about any other part.
What is undercoverage?
occurs when some groups in the population are left out of the process of choosing the sample
What is nonresponse?
occurs when an individual chosen for a sample can’t be contacted or refuses to participate
What is response bias?
occurs when survey respondents answer falsely, either deliberately or by mistake
