Defining and collecting data vocabulary

Categorical

Qualitative; Variables take categories as their values that are true or represent different groups.

Numerical

quantitative; variables have value that represent a counted or measured quantity.

Discrete numerical

Variables arise from a counting process

Continuous numerical

Variables arise from a measuring process

Nominal Scale

Classifies data into distinct categories in which no ranking is implied

Ordinal scale

Classifies data into distinct categories in which ranking is implied

Interval scale

an ordered scale in which difference between measurements is a meaning quantity but the measurements do not have a true zero point.

Ratio scale

Is an ordered scale in which the difference between the measurements is a meaningful quantity and the measurements have a true zero point

Population

Contains all of the items or individuals of interest that you seek to study

Sample

Contain only a portion of a population of interest

Population parameter

Summarizes the value of a specific variable for a population

Sample statistic

Summarizes the value of a specific variable for sample data

Primary source

When a data collector is the one using the data for analysis such as surveys, interviews, or original research.

Secondary Sources

The person performing data analysis is not the data collector

Coverage error or selection bias

Exists if some groups are excluded from the frame and have no chance of being selected

Nonresponse error or bias

People who do not respond may be different from those who do respond

Sampling error

Variation from sample to sample will always exist

Measurement error

Due to weaknesses in quesiton design and/or respondent error