Statistical graphics:

A statistical graphic is data presented in a graphical format.

A well designed statistical graphic also refered to as chart or graph.

Use of statistical graphics

• Reserve for material that is rich, complex or difficult.
• Data Presentation
• Emphasize the data
• Minimize non data elements
• Minimize redundant data
• Fill the graph's available area with data.
• Show data variation
• Provide proper context for datà interpretation

Scales and shading

• Place ticks to marks scales on the outside edge of each axis.
• Employ a linear scale.
• Mark scales at standard or customary intervals
• Start a numeric scale at zero.
• Display only a single scale on axis.
• Provide scaling consistency
• Consider duplicate axis for large scale data.
• Proportion
• Lines
• Labeling
• Title
• Interpretation of numbers

Types of statistical graphs

(1) Curve and line graphs

(2) Single graph

• Four or five maximum
• Label identification
• Legend
• Tightly packed curves
• Important or critical data
• Comparing actual and projected data
• Data differences

(3) Surface charts

• Ordering
• Coding schemes
• Labels

(4) Scatter plots

• Two dimensions
• Consistent intervals
• Multiple data sets
• Significant points

(5) Bar Graph

• Consistent orientation
• Meaningful organization
• Bar spacing
• Differentiation
• Important or critical data
• Related bar ordering
• Reference index
• Labeling

(6) Segmented or stacked bars

• Data category ordering
• Large segments
• Coding schemes
• Labeling

(7) Flow charts

• Order of stps
• Orientation
• Coding conventions
• Arrows
• Highlighting
• One decision at each step
• Consistently order and word all choices