The Scientific Method Tables, Charts and Diagrams

Data presentation in graphs must follow certain conventions There must be a clear and self- explanatory title Standard error or deviation may be shown as bars above and below the plot point. A line of best fit may join the points The dependent variable is plotted on the vertical (y) axis. Axes must be fully labelled and SI units of measurement shown Points must be accurately plotted and different symbols used to plot multiple data sets A key should identify the meaning of all symbols used Each axis should have an appropriate scale – a break in an axis can help make best use of the plot area if there are no data in this range Lecture 4: Tables, Graphs and Diagrams Conventions

The relationship between continuous variables is usually depicted in: A scatter graph – used to show relation-ships between variables. A line of best fit may be approximated or calculated to quantify the relationship A line graph – usually used to show the effect of changing an independent variable on the values of the dependent variable Two or more sets of related data can be shown on one scatter or line graph by double labelling of vertical axes, conventionally shown to right and left, with appropriate scaling Lecture 4: Tables, Graphs and Diagrams Graph types

Pie charts are suitable for discontinuous data Kite diagrams are useful in ecological surveys where it is often necessary to show how the relative quantities of organisms change in space Quantities for each category are plotted equally on either side of a centre line Graph types