Definitions
A subset of a population used for research
What is a Sample?
A market researcher surveys 85 people on their coffee-drinking habits. She wants to know whether people in the local region are willing to switch their regular drink to something new. The sample is...
What is "the 85 people surveyed"?
The sampling method in which the people who respond to the survey question choose themselves.
What is Voluntary Response Sampling?
The head chef of a restaurant wants to know if he should add more vegetarian options to his menu. To find out the demand for vegetarian dishes amongst his customers, he sends out an email to everyone on the mailing list of the restaurant asking them to fill out a survey.
What is Voluntary Response Sampling?
What college or university does Ms. Wanner's oldest son go to?
Full Sail University
All members of a group that you are looking to make generalizations about.
What is a Population? Or What is the Target Population?
The state Department of Transportation wants to know about out-of-state vehicles that pass over a toll bridge with several lanes. A camera installed over one lane of the bridge photographs the license plate of every tenth vehicle that passes through that lane. The population is...
What is "all of the vehicles that pass through"?
The sampling method in which the sample is chosen randomly from the population.
What is Simple Random Sampling?
An elementary school principal wants to know more about the prevalence of learning disabilities at her school. She randomly selects 2 grades and has all the children in those grades tested by an educational psychologist.
What is Cluster Sampling?
What sport does Ms. Wanner and her sons like to do together?
Ski
This refers to the extent to which the results of a study can be generalized beyond the specific conditions, participants, and settings of that study. It answers the question: "Can the findings of this study apply to other populations, settings, or times?"
What is External Validity
A factory overseer selects 40 threaded rods at random from those produced that week at the factory, then she tests their tensile strength. The sample is...
What is "the 40 threaded rods selected"?
The sampling method in which the population is divided into groups and entire groups are chosen to be part of the sample.
What is Cluster Sampling?
A university wants to find out how far the average student lives from the campus. To investigate this matter, a random number generator is used to select a sample of 250 students from the student registry.
What is Simple Random Sampling?
How long has Ms. Wanner been teaching Math?
28 years!
A sample that looks like the population it was drawn from.
What is a Representative Sample?
The owners of a sports stadium wanted to predict what additional refreshment options would sell well. They selected 808080 seat numbers at random and surveyed the occupants of those seats. The population is...
What is "the occupants of all seats in the stadium"?
The sampling method in which the population is split into groups and then individuals are chosen randomly from each group.
What is Stratified Random Sampling?
A Ph.D. student is looking for research participants for her dissertation. She decides to recruit the subjects of her study by asking students on campus if they would be willing to sit down for an interview.
What is Convenience Sampling?
What is the name of Ms. Wanner's oldest son's band?
Private Drive
A sample that is NOT representative of the population it was drawn from.
What is a Biased Sample?
A city council member wanted to know how her constituents felt about a planned rezoning. She randomly selected 757575 names from the city phone directory and conducted a phone survey. The Parameter of Interest is...
What is "how people feel about planned rezoning"?
The sampling method in which the population is listed and numbered. The sample is chosen by randomly selecting individuals using a specified interval.
What is Systematic Sampling?
You want to find out what each students' favorite subject is. You divide a school population into groups based on grade level and then create a sample by randomly selecting students from each grade level.
What is Stratified Random Sampling?
What is the name of Ms. Wanner's horse?
Kiwi