Graphing PreAP Biology Why do we graph data

Graphing Pre-AP Biology

Why do we graph data? 34 55 32 • By graphing the data, we can more easily make sense of it. • Graphs are pictorial diagrams that represent numerical data. 0% % 10 3 . 9 50 . 6 85 % 5 . 9 76 0 . 0 97 % 88 % 0 . 0 34 $1 31 $2 50 $4 19 $3 $7 0

Interpreting graphs

What relationship is being portrayed in this graph?

What relationship is being portrayed in this graph? This graph shows the effect of different concentrations of fertilizer on the growth of three different types of plants.

Describe the results shown for corn plants.

Describe the results shown for corn plants. For corn plants, the higher the concentration of fertilizer, the taller the plants will grow.

Describe the results shown for oak seedlings.

Describe the results shown for oak seedlings. As the concentration of fertilizer is increased, growth of oak seedlings is improved, up to a certain point.

Describe the results shown for rose bushes.

Describe the results shown for rose bushes. For rose bushes, increasing the concentration of fertilizer inhibits plant growth.

For which plant is this fertilizer least effective at higher concentrations?

For which plant is this fertilizer least effective at higher concentrations? Rose bush

Predict how tall corn plants might be when the fertilizer concentration is 75 mg/L.

Predict how tall corn plants might be when the fertilizer concentration is 75 mg/L. The plants will be about 12 - 13 cm in height.

Making a graph

Making a graph

Making a graph

Making a graph

Making a graph • One way to remember which data goes on which axis is the acronym DRY MIX.

Making a graph Title: • Write an appropriate title for the graph at the top. • The title should contain both the independent and dependent variables.

Making a graph Scale: • Decide on an appropriate scale for each axis. • The scale refers to the min and max numbers used on each axis. They may or may not begin at zero. • The min and max numbers used for the scale should be a little lower than the lowest value and a little higher than the highest value. • This allows you to have a smaller range which emphasizes the comparisons/trends in the data.

Making a graph: Choosing a scale

Making a graph Intervals: • Look at your minimum and maximum values you set up for both the Y and X-axis. • Decide on an appropriate interval for the scale you have chosen. The interval is the amount between one value and the next. • It is highly recommended to use a common number for an interval such as 2, 5, 10, 25, 100, etc.

Making a graph: Choosing an interval

Making a graph Labels: • Both axes need to be labeled so the reader knows exactly what the independent and dependent variables are. • The dependent variable must be specific and include the units used to measure the data (such as “number of drops”).

Types of graphs • Line graphs: Used for data that is connected, such as over a period of time. Lines consist of connected dots. • Bar graphs: Used for data that is not connected, such as categories. • Pie charts, data tables, etc….