2.3 Additional Displays of Quantitative Data

class midpoint

sum of consecutive lower class limits divided by 2.

frequency polygon

uses line segments connected to points located directly above class midpoint values in a
histogram.

cumulative frequency distribution

displays the aggregate frequency of the category. total number of observations less than or equal to the category.(discrete data) and displays the total number of observations less than or equal to the upper class limit of a class (continuous
data)

ogive

a graph that represents the cumulative frequency or cumulative relative
frequency for the class.

time series data

the value of a variable is measured at different points in time

time-series plot

obtained by plotting the time in which a variable is measured on the horizontal axis and
the corresponding value of the variable on the vertical axis.