Frequency Distribution
An organized tabulation showing exactly how many scores exist in the data set for a category
Frequency Distribution Table
A table with 2 columns; categories on the scale of measurement (X) and frequency (f)
Grouped Frequency Table
The X column lists groups of scores called class intervals or bins (same width)
Histogram
A bar centered above each score or class interval and good for shape of distribution of data (bars touch one another)
Polygon
A dot is centered above each score and a continuous line is draw to connect each dot
Interpolation
Scores and the percentages change in a regular, linear fashion as you move through an interval
Normal Distribution
When the left side of the graph is a mirror image of the right side
Skewed Distribution
When scores pile up towards one end of the scale and taper off gradually at the other end
Positive Skew
When the tail goes to the right (scores are on the left)
Negative Skew
When the tail goes to the left (scores are on the right)
When to use Scatterplots
When you want to show the relationship between two variables
When to use Bar Graphs
When you want to show frequencies or the average level of a scale variable for a nominal or ordinal value
When to use Line Graphs
When you want to show the relationship between two scale variables using a line over a period of time
