Charts and Graphs

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Charts and Graphs
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Variables

• Variables are things that we measure, control, or
  manipulate in research.
• Independent variables are variables whose values
  are independent of changes in the values of other
  variables.
• Independent variables are those that are
  manipulated whereas dependent variables are only
  measured or registered.

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Organizing Data

• There are several ways Scientists organize the
  data collected during their experiments.
• Tables, charts and graphs are convenient ways to
  clearly show your data. Be sure to consider how
  to best show your results with appropriate graph
  forms.
• Be sure to give your charts and graphs an
  appropriate title that explains what the data
  measures.

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Line Graphs

• A line graph is used to show continuing data how
  one thing is affected by another. It's clear to
  see how things are going by the rises and falls a
  line graph shows. This kind of graph is needed to
  show the effect of an independent variable on a
  dependent variable.

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In the sample below, the pulse rate of a person
is shown to change over time. As time continues,
the pulse rate changes. A typical chart or table
for this graph might look like this  
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Examples
Age/ contribution by age
Population Growth
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Bar Graphs

• Bar graphs are a very common type of graph best
  suited for a qualitative independent variable.
  Since there is no uniform distance between levels
  of a qualitative variable, the discrete nature of
  the individual bars are well suited for this type
  of independent variable.

• Though you can extract trends between bars (e.g.,
  they are gradually getting longer or shorter),
  you cannot calculate a slope from the heights of
  the bars.

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Examples
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Circle or Pie Chart

• A circle graph is used to show how a part of
  something relates to the whole. This kind of
  graph is needed to show percentages effectively.
• A typical chart or table for this graph might
  look like this

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Examples