Graphing in Science

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Parts of a Graph

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(y-axisdependent variable)

(x-axisindependent variable)

Line Graphs• Line graphs compare two variables (one is

often time).

• For displaying data or information that changes continuously over time.

• They enable the viewer to make predictions about the results of data not yet recorded .

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Line Graph Set-Up

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Pie Graphs• Pie graphs (sometimes called circle charts)

are used to show the parts that make up a whole.

• They can be useful for comparing the size of relative parts. 

• Usually used for percentages (%).

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Pie Graph

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Bar Graphs• Make comparisons between

different groups (variables). • The bars do not touch.

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Bar Graph

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Bar Graphs Set-Up

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Histograms• Use histograms when y-axis gives the rate

of, or occurrences for continuous data that has been sorted into groups, for example, 20-24 meters.

• All bars are usually of equal width.

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Histograms

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Histogram Set-Up

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Scatter Plot Graphs• Scatter plots has points that show

relationship between two sets of data (e.g., students’ study time and their grades).

• Scatter plots usually consist of a large body of data. The closer the data points come when plotted to making a straight line, the higher the correlation (relationship) between the two variables, or the stronger the relationship.

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Scatter Plot Graph

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Scatter Plot GraphsIf there is absolutely no correlation present then R2 =

0

The closer R2 is to 1 or -1, the stronger the correlation, or the stronger the relationship between the variables

The closer R2 is to 0, the weaker the correlation

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Scatter plot graphs• A perfect positive

correlation is given the value of 1

• A perfect negative correlation is given the value of –1

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