Transcript Slide 1

The Scientific Method
Tables, Charts and Diagrams
Conventions
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Data presentation in graphs must follow certain conventions
There must be a
clear and selfexplanatory title
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
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
Standard error or deviation may be
shown as bars above and below the
plot point. A line of best fit may join
the points
A key should identify the meaning of all
symbols used
Graph types
The relationship between continuous variables is usually depicted in:
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Surface Area cm
A scatter graph – used to show relation-ships
between variables. A line of best fit may be
approximated or calculated to quantify the
relationship
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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
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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