Topic_1-Intro_to_Stat-level_of_measurements_1pp

Statistics

The science of the collection, organization, analysis, and interpretation of data.

Population

All of the objects that researchers want to describe or make inferences about.

Sample

A sub-group of the population that the researcher believes represents the population.

Descriptive Statistics

Methods that organize, describe, and summarize a small dataset, where results represent the entire dataset.

Inferential Statistics

Conclusions about populations derived from small (random) samples, often used to determine cause and effect relationships.

Dependent Variable (DV)

The variable of primary interest that is measured to observe changes in response to the independent variable.

Independent Variable (IV)

A variable that is manipulated to observe the effects on the dependent variable.

Levels of Measurement

The classification of data into nominal, ordinal, interval, and ratio levels.

Nominal Data

Data placed in categories with no ordering, cannot be quantified.

Ordinal Data

Data that is ranked, indicating a relative position but does not quantify the difference between ranks.

Interval Data

Data with equal units of measurement, but zero is arbitrary and does not indicate the absence of the variable.

Ratio Data

Data similar to interval data, but zero is absolute, indicating an absence of the variable.

Quantitative Variables

Numerical data that can be added, subtracted, multiplied, or divided.

Qualitative Variables

Characteristics that can be categorized or classified based on attributes.

Random Sample

A sample selected in such a way that every member of the population has an equal chance of being included.

Mean

The average of a set of values, calculated by summing all values and dividing by the number of values.

Standard Deviation

A measure of the amount of variation or dispersion in a set of values.

Variance

The square of the standard deviation, representing how far a set of numbers are spread out from their mean.

Histogram

A graphical representation of the distribution of numerical data through bars.