Graphs and diagrams

LINE

• Simple- to show a single set of data
• Compound- if data can be sub-divide into 2 or more sets of data
• Comparitive- comparing 2 sets of data on the same axis 
• Divergent- where the x axis is in the middle so both negative and postive data points can be shown on one set of axis

BAR

• Simple- Single series of data in categories
• Comparitive- show 2 sets of data on the same graph
• Compound- Show how the total in one bar is divided up between a number of subtotals 
• Divergent- same as divergent line graph but with categories 

• The relationship between two sets of variables is shown. The line of best fit allows analysis of the data to be made. 
• Independant variable along the x axis
• Dependent variable along the y axis

ADVANTAGES

• Easy to spot anomalies
• Strength of correlation can be confirmed using a statistical test
• The line of best fit can be used to predict future data sets

DISADVANTAGES

• Doesnt show cause and effect
• 'overplotting' can be an issue with lots of similar results
• Have to have continuous data

• Total divided by different sets (%) X 306 = proportions

ADVANTAGES

• Clear visual representation of the data
• Able to compare easily 
• Relitively easy to construct

DISADVANTAGES

• May not show numerical data
• May get overcrowded if there are too many divisions
• Nominal data only 

A scatter graph which shows 3 variables and how they are interrelated

ADVANTAGES

• Visual relation of 3 data sets and how they link
• % are plotted which are especially easy to compare
• Shows clusters of data

DISADVANTAGES

• Raw data must be converted into %
• Can be difficult to interpret, especially if there is a lot of data. 

• Often show direction eg.wind speed + direction
• The points on the outside can be compass points or months of the year etc
• The distance the bars reach from the centre shows the size of the variable
• Most common radial diagram is a wind rose
• Used for continual cycles

ADVANTAGES

• Displays multiple data variables
• Visual

DISADVANTAGES

• Suitable only for continuous data
• May only show general trends if based on averages
• Can be difficult to read/ interpret.

• Lets you fit very wide range of data onto one axis without having to draw a huge graph
• Semi- Log is when the Y axis is logarithmic and the X axis linear.
• Full-log is when both axis are logarithmic 
• Used for population graphs due to the huge range

ADVANTAGES

• Allows you to work with large range of numbers
• Shows overall trend/ unseen patterns that normal graphs cant show 

DISADVANTAGES

• Positive and negative values cannot be plotted on same graph
• 0 cant be plotted
• Makes accuratly reading off the scale hard 

• Box and whisker plots use to show the spread around the mean 
• Cross between a tally chart and a bar chart
• range of data on 1 axis and frequency on the other
• Each dot represents one piece of information
• Doesnt give you the precise data points as it is grouped together in intervals

• Thickness shows number/percentage of each data set at a point in time
• Thickness is balanced equally above and below the line
• Used usually to plot species distribution along a transect

ADVANTAGES

• Visual representation of change and progress over a specific distance
• Uses raw data and %
• Comparisons can be made between different species

DISAVANTAGES

• Limited to transect lines
• Only suitable for specific data with specific purpose
• Visually subjective- the scale can affect the diagram