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Histograms, Frequency Polygons, and Time Series Graphs

Histograms

Frequency Polygons

Time Series Graph

Use it when the data set consists of 100 values or more.

The horizontal axis is labeled with what the data represents

The vertical axis is labeled either frequency or relative frequency. RF = f/n

The number of bars needs to be chosen.

Choose a starting point for the first interval to be less than the smallest data value.

Decide how many bars or intervals

Make continuous data visually easy to interpret

Examine the data and decide on the number of intervals

Choosing the appropriate ranges

Begin plotting the data points

Draw line segments to connect them.

Are useful for comparing distributions

This is achieved by overlaying the frequency polygons drawn for different data sets.

Make trends easy to spot

Are important tools in various applications of statistics

Must look at both pieces of our paired data set.

Start with a standard Cartesian

The horizontal axis is used to plot the date or time increments

The vertical axis is used to plot the values of the variable that we are measuring.

Each point on the graph correspond to a date and a measured quantity.