Stats definitions Flashcards
Qualitative data
non numerical data
Quantitative data
numerical data
continuous data
data that can take any value and range e.g time
discrete data
-data that can only take certain values
correlation
a measure of how closley 2 quantities are linearly related
population
The whole set of items that are of interest
census
Observes or measures every member of a population
sample
Selection of observations taken from a subset of the population
sampling unit
An individual item of a population
sampling frame
A unique numbering or naming of sampling units to form a list
simple random sampling
random sampling technique in which every member of the population has an equal chance of being selected
systematic sampling
Random sampling technique in which elements are chosen at regular intervals from an ordered list
stratified sampling
Random sampling technique in which the population is divided into mutually exclusive strata (classifications) and a random sample is chosen from each, maintaining the population’s proportions lying within each strata
Quota sampling
Non-random sampling technique in which a sample is chosen by the researcher to represent the characteristics of the whole population
Opportunity (convenience) sampling
Non-random sampling technique in which elements are selected based on availability at the time of sampling, chosen to fit required criteria.
continuous variable
A variable that can take any value in a given range
discrete variable
A variable that can take only specific values in a given range
sample space
The set of all possible outcomes
Probability distribution
A full description of the probabilities of any outcome in the sample space
Test statistic
An observation or statistic calculated from a sample, used to test a hypothesis
Actual significance level
The probability of incorrectly rejecting the null hypothesis (ie the chance that an observed result would fall in the critical region purely by chance if the model assumed by the null hypothesis were true).
Binomial model
Where there are a fixed number of trials; exactly two possible outcomes; a fixed probability of success at each trial and trials are independent of each other
Conditional probability
When the known occurrence of one event effects the probability of subsequent events.
Critical region
A region of the probability distribution which, if the test statistic falls within it, leads to a rejection of the null hypothesis