Collecting Data

Parameters

Variables or factors that define the data collection process for population, specifying the elements to be measured and the conditions of the study.

Population

Number that describes a population, it is a fixed number but the value is unknown.

Statistics

Number that describes a sample. The number is known but it varies from sample to sample.

Population

The complete set of individuals or items that share a characteristic of interest in a statistical study, from which a sample may be drawn.

Sample

A subset of individuals or items selected from a population for the purpose of conducting a statistical analysis.

Convenience sample

A type of non-probability sampling where individuals are selected based on their easy availability and proximity to the researcher, rather than random selection.

Bias

A systematic error introduced into sampling or testing that skews results, often leading to inaccurate conclusions.

Voluntary response

A type of sampling where individuals self-select to participate, often leading to biased results because those with strong opinions are more likely to respond.

Simple random sample

A sampling method where every individual in a population has an equal chance of being selected, ensuring that the sample is representative.

Table of random digits (D Table)

A tool used in statistical sampling that contains a sequence of random digits, allowing researchers to select random samples from a population.

Stratified random sample

A sampling method that divides the population into distinct subgroups, or strata, and then randomly samples from each stratum to ensure representation across key characteristics.

Cluster sample

A sampling method that divides the population into clusters, typically geographically, and then randomly selects entire clusters to represent the population.

Sampling errors

Errors that occur when a sample does not accurately represent the population from which it was drawn, often leading to biased results.

Undercoverage

A sampling error that occurs when some members of the population are inadequately represented or excluded from the sample, leading to biased results.

Nonresponse

A type of sampling error that occurs when individuals selected for the sample do not respond, leading to potential bias in the results.

Processing errors

Errors that occur during data entry, analysis, or recording, which can lead to inaccurate results or conclusions.

Response errors

Errors that occur when respondents provide incorrect answers due to misunderstanding, forgetfulness, or intentional deception, affecting the accuracy of data collected.

Wording

The way questions are phrased in a survey or interview that can influence respondents' answers and potentially skew results.