Categorical Data

Data that can be grouped by specific, non-numerical categories

Quantitative data

data that can use numeric values to indicate how much or how many

Descriptive Statistics

Summaries of data in a form that is easier for the reader to understand

Includes tabular, graphical, and numerical presentations of the data

Population

The set of all elements of interest in a particular study

Sample

A subset of the population

Statistical inderence

The use of data from a sample to make estimates and predictions about the characteristics of a population

Frequency Distribution

A tabular summary of data showing the number of observations in each of several non-overlapping categories

Relative Frequency

The fraction or percentage of observations belonging to a class

Histogram

A bar graph in which the classes are marked on the horizontal axis and the class frequencies on the vertical axis

Class frequency is shown by height of the bar with the bars being shown adjacent to each other

Scatter Diagram

A graphical display of the relationship between two quantitative variables

Treadline

A line that provides an approximation of the relationship between two variables

Mean

The average value for a variable

Provides a measure of the central location for the data

Parameter

Characteristic of population

Statistic

A characteristic of a sample

Median

Another measure of the central location. It is the value in the middle when the datas are arranged in ascending order

Mode

another measure of central locations. it is the value that occurs with the greatest frequency

Variance

a measure of variability that utilizes all the data

Standard Deviation

The positive square root of the variance

z-score

standardized value. it is the number of standard deviations a data value (x) is from the sample mean