Elements
entities on which data is collected
variable
characteristic of interest for the elements
observation
measurements obtained for a particular element
Nominal scale
labels or names used to identify an attribute of the element
ordinal scale
order of data is meaningful
interval scale
tell us about the order of data points, and the size of the intervals in between data points
Ratio scale
has a true zero point
Categorical data
uses nominal or ordinal scale, labels, and can be numeric or non-numeric
Quantitative data
indicates how much or how many, always numeric
Frequency Distribution
tabular summary of data showing the frequency of items in each non overlapping classes
Relative Frequency
fraction of the total number of data items belonging to the class
Percent Frequency
the relative frequency multiplied by 100