Probstat

Median

The midpoint of an array of numbers or observations.

Mode

The score or observation that appears the most number of times in a distribution.

Primary data

Raw data that has only been obtained from the source and has not gone through any kind of statistical treatment.

Secondary data

Data that has already been obtained by others and can be categorized, tabulated, and statistically handled.

Sampling

A technique that enables researchers to infer population information on the basis of results from a subset of the population.

Simple Random Sampling

Each person is chosen entirely by chance; every member of the population has an equal chance of being chosen.

Systematic Random Sampling

Individuals are picked from the sampling frame at regular intervals.

Stratified Random Sampling

The population is divided into subgroups (strata) that share a common characteristic.

Cluster Random Sampling

Subgroups of the population are used in a clustered survey as the sampling unit.

Convenience Sampling

Participants are chosen based on availability and willingness to participate.

Quota Sampling

Interviewers are given a quota of subjects of a specified sort to attempt to recruit.

Purposive Sampling

Also known as selective sampling, it relies on the researcher's judgment to decide participants.

Frequency Distribution

A visual representation for the distribution of observations within a specific test.

Textual Form

The raw and ambiguous form of data presentation, usually in written form.

Tabular Form

Data representation in a structured table format, which is easy to read.

Graphical Form

Data presentation through diagrams, which play an important part in visualizing statistical results.

Histogram

A graphical data display using bars to group numbers into ranges.

Frequency Polygon

A graphical representation used to reflect the shape of data and depict patterns.

OGIVE

Graphs used to estimate how many numbers in data lie below or above a given variable.

Pie Chart

A circular graph where each piece represents a fraction of the whole.

Descriptive statistics

A branch of statistics that includes the organization, display, and description of data.

Inferential statistics

A branch of statistics involving drawing conclusions about the population based on sample information.

Population

The groups of people in a survey that reflect the whole community to be studied.

Sampling error

Errors that may negatively affect the representativeness of a sample in relation to the population.

Variable

A property or feature of a person, event, or object that may have different values.

Interval scale

A scale where there is an order and the difference between two values is important.

Ratio variable

A variable that has all the characteristics of an interval variable and can have a value of 0.