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The appropriate type of graph depends on the type of data.
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The basis for the choice of what graph to construct is the independent variable, the principal character.
BAR GRAPH
If the independent variable is in the word form, the appropriate graph is a bar graph.
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It compares values across categories.
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Steps in constructing a data table:
Construct a data table with columns containing the independent and dependent variables and derived quantities. Subdivide the column of dependent variable to indicate the number of trials. Record the values of the independent variable in the rows under the column of independent variable. Record the values of the dependent variable that corresponds to each value of the independent variable. Calculate the derived quantity and enter the values in the table.
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Sample Data Table: table 5. the effect of fertilizer on the height of plants
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Steps to construct a bar graph for the data: 1. Prepare a bar graph using the data below. Draw and label the X and the Y axes of the graph. The x-axis contains all the points for one set of data and also the y-axis.
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2. Write data pairs. You may round off the numbers. Control: A - 20.6 Horse manure: B - 32.6 Urea: C - 30.8 3. Determine scales for axes 4. Plot data pairs. 5. Draw the bars.
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6. Summarize trend. Plants grown in soil with horse manure are the tallest.
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Line Graph
If the independent variable is in number form, you can use a line graph.
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It is composed of X and Y axes.
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Line with markers is displayed at each data value.
Steps in constructing a line graph: 1. Construct a data table similar to the table you have constructed for the bar graph.
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2. Draw and label axes of the graph. 3. Write data pairs. 4. Determine scales for axes. 5. Plot data pairs. 6. Join the points to form a line. 7. Summarize trends. As the amount of fertilizer increases, the height of the plant increases. Beyond a certain amount, increase in height is slow.