Statistics Flashcards
What is a population?
A whole set of items that are of interest
What is a census?
(A set of data that) observes or measures every member of a population
What is a sample?
A selection of observations taken from a subset of the population which is used to find out information about the population as a whole
What is a sampling unit?
An individual unit of a population
What is a sampling frame?
When sampling units of a population are individually named, or numbered, to form a list
What happens in a simple random sample?
(If it is of size n) every sample of size n has an equal chance of being selected
What happens in systemic sampling?
The required elements are chosen at regular intervals from an ordered list
What happens in stratified sampling?
The population is divided into mutually exclusive strata (e.g. males and females), and a random sample is taken from each
What happens in quota sampling?
An interviewer or researcher selects a sample that reflects the characteristics of the whole population
What happens in opportunity sampling?
You take the sample from people who are available at the time the study is being carried out, and who fit the criteria you are looking for.
What are quantitative variables/quantitative data?
Variables or data associated with numerical observations
What is qualitative data/qualitative variables?
Variables or data associated with non-numerical observations
What is a continuous variable?
A variable that can take any value in a given range
What is a discrete variable?
A variable that can take only specific values in a given range
What are classes?
The groups found when data is presented in a grouped frequency table, and the specific values are not shown.
