Data Presentation is not a mystery!

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Data Presentation is not a mystery!

• Graphs
• Tables

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An Experiment

• The hypothesis is pea plants sprayed with
  gibberellic acid will be taller because of
  greater internode elongation.
• The control plants are sprayed with distilled
  water and the experimental plants sprayed with a
  dilute solution of gibberellic acid. There are 10
  plants per treatment.
• Plant heights are measured for 5 days in row on
  the fifth day the number of leaves and the second
  internode from the apex is measured.
• What follows is how the data will be presented.

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Graph construction

• You have height data over time for control and
  treatment pots.
• Each pot consisted of several plants.
• Each day after spraying you measured plant
  height.
• Plot the average height of all of your plants in
  the control pots versus time.
• Plot the average height of all of your plants in
  the treatment pots versus time.
• Put both plots on the same piece of graph paper.

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Graph Basics

• Graphs always have axes.
• Graphs always use the whole piece of graph paper.
• Graphs always have titles and are numbered
• Graphs always have axes titles
• Graphs always have units given in the axes titles
• A graph always have appropriate tick marks
• A graph can have a legend

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Graphs always have axes.
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Graphs always use the whole piece of graph paper!!
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A graph always has a title and are numbered.
Figure 1. The Effect of Gibberellic Acid on Pea
Plant Growth
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A graph always has axes titles.
Figure 1. The Effect of Gibberellic Acid on Pea
Plant Growth
Time (days)
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A graph has appropriate tick marks
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There is a trend line for each data set.

• For our purposes we will assume a linear
  relationship unless it is indicated otherwise.

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A graph should have a legend
Figure 1. The Effect of Gibberellic Acid on Pea
Plant Growth
Gibberellic acid spray
Control
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Table Construction.

• Your have control and treatment plots.
• Report the mean internode length and of leaves
  for all of the pea plants in the control pot.
• Report the mean internode length and of leaves
  for all of the peas in the treatment pot.
• Report this information in the same table.

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Table Basics

• Tables always have titles.
• Tables always are numbered.
• Tables always have headings for columns and rows.
• Tables always indicate what the units are.
• Tables summarize data.

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Tables always have titles!
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Tables always are numbered.
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Tables always have headings for columns and rows.
Gibberllic Acid Treatment
Observation
Control
Mean Internode Length (cm)
Mean Number of Leaves per Plant
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Gibberllic Acid Treatment
Observation
Control


Mean Internode Length (cm)


Mean Number of Leaves per Plant
2nd internode from apex
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Other Data

• Report your qualitative data using sentences.

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Finishing Thoughts

• Tables and Figures used in reports summarize
  data.
• Never report the same data in both a Figure and a
  Table.
• Always encapsulate the relevant points of a
  Figure or Table using data points (the numbers)
  in one or more well constructed sentences in the
  text.
• Tables and Figures appear in the text of the
  report as soon after they are referred to as
  possible, not in a separate section at the end of
  the paper.

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Data presentation is really black and white!