BIO111: PRINCIPLES OF BIOLOGY 2018
TUTORIAL 1
Data collected during an investigation should be organized, manipulated, summarized, and presented to reveal trends (patterns, relationships). This can be done by using tables, graphs, pictures, and diagrams). A decision has to be made on the best way of presenting the data.
NOTE: Results are part of the scientific method, so they form part of the investigation.
Therefore the data presentation should be in line with:
What question are you attempting to answer/
What is your hypothesis?
What is your prediction?
Presenting data in a table
The data in table 1 show the results of an experiment in which two strains of maize were each grown in soils with varying amounts of nitrogen.
Table 1: The effect of soil nitrogen on the amount of grain produced by two strains of maize
Nitrogen in the soil
(kg/hectare)
2
Grain yield (kg/hectare)
Maize strain 1 Maize strain 2
3000 1800
30 3100 2200
60
90
120
3200
3600
3650
3500
3800
4600
▪ The title should be
clear, concise, informative, and appropriate
preceded by a Table number
above the table
▪ The columns and rows should be clearly labeled with
appropriate headings
appropriate units
▪ Does Table 1 reveal the pattern/trend?
Is there another way in which the data could be better presented?
Presenting data in a graph
Present the data in Table 1 in a graph.
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▪ What type of graph should you use to present the data?
Line graph for continuous quantitative variables
Histogram for continuous quantitative variables
Bar graph for discrete quantitative or qualitative variables
▪ What is a quantitative variable? Give an example.
▪ What is a qualitative variable? Give an example
▪ What is a continuous variable? Give an example
▪ What is a discrete variable? Give an example
▪ Size and layout
Graph must occupy at least half of an A4 page
Leave enough space for labeling axes
Provide a legend, including a key to any symbols used
▪ Axes
Must be clearly labeled with appropriate units
Which is the independent variable? This should be plotted on the horizontal axis
Which is the dependent variable? This should be plotted on the vertical axis.
▪ In many cases, it is better to draw a best straight line or curve than to connect the dots.
▪ If there are two or more curves in the graph, clearly distinguish between them by using different symbols/notation.
▪ The title should be
clear, concise, informative, and appropriate
preceded by a Figure number
below the graph
NOTE
▪ After presenting data in a table or graph, draw the reader’s attention to your findings by summarizing the most important trends.
▪ Never present the same data in both a graph and a table.
▪ When average values (arithmetic means) are used
include the amount of variation in the data presented in the table
add a bar extending from each point in a graph to show the amount of variation
(This point will be discussed later in the lab)
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