Analyzing your data: Variables and Graphing

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Analyzing your dataVariables and Graphing
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Organizing your data

• In any investigation, organizing is the first
  step to finding answers. Once you conduct an
  experiment, you must organize your data.
• Always create a data table before your experiment
  starts, that way you can keep your data organized
  as you work.
• A data table has two columns to list the two
  variables in your experiments.

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Variables
independent

• VARIABLES are the things that change in an
  experiment.
• In a data table there are two types of variables
  
• 1. INDEPENDENT VARIABLES The factor that the
  scientist changes
• On the Left side in a data table and the x-axis
  of a graph
• Examples every week (the weeks are changing)
• Distance, Amount, Time

Time (min) Distance (m)
5 3
6 6
7 9
8 12
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Variables cont.
Temperature in Celsius Students who got sick
150 500
200 80
300 20
500 0
dependent

• DEPENDENT VARIABLE THE FACTOR THAT CHANGES
  BASED ON THE INDEPENDENT VARIABLE-.
• On a data table the dependent variable is on the
  right side.
• On a graph it is on the y-axis.
• Examples
• Temperature record the temperature as it changes
  after set periods of time.
• Mass- Mass of each object after something has
  affected the object.

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Controlled vs. Variable Parameters

• 1. VARIABLE PARAMETER (independent variable and
  dependent variables) this is the things you
  change in the experiment.
• 2. CONTROLLED PARAMETERS these are all the
  other factors in the experiment that stay the
  same.

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Data Tables
Day of the Week Hours of Sleep
M 8
T 10
W 12
Th 6
Type of Antibiotic Pathogens (1000x)
Penn. 500
Doxy. 80
Amox. 20

Amount of Protein (g) Muscle Growth (cm)
150 5
200 10
300 3
500 0
Temperature in Celsius Students who faint in formation
38 20
39 23
40 50
41 100
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Examples figure out which is the independent and
dependent variable

1. A scientist checks how much his puppy grows each
   day for 20 days.
2. A science student adds salt to 3 fish tanks at
   different rates to see how fast algae will grow
   in each tank.
3. A student records how fast the cars go on the
   freeway at 5 different times during the day.
4. A scientist takes the temperature of a beaker of
   cooling chemicals every 2 minutes.

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Graphing

• Data tables help you organize data, Graphs help
  you understand and use the data.
• Graphs make it easy to identify trends and make
  predictions.
• TREND The relationship
• between the independent
• and dependent variable
• (THE LINE)

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Steps for Making a Graph

• 1. Draw the Axes use the data table to determine
  the graphs axes. The Independent variable goes
  on the x-axis, the Dependent variable goes on the
  y-axis.
• 2. Label the axes title each axis with the
  appropriate info.

Years Population
1980 20
1990 23
2000 50
2010 100
Dependent Population
Independent Years
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Steps Cont.
Amount of Protein (g) Muscle Growth (cm)
150 5
200 10
300 3
500 0

• 3. Determine the Range and the Scale
• to find the RANGE subtract the smallest value of
  a single variable from the largest value
• For our Data 500-150 350, so the x-axis must
  cover at least 350 grams. 10-0 10 so the y-axis
  must cover at least 10 cm.
• The SCALE is the size that is used for each box
  on the graph. There can be a separate scale for
  each axis. The scale should be chosen such that
  the graph spreads out to fill most of the
  available space. The scale must go in equal
  increments

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Scale
Amount of Protein (g) Muscle Growth (cm)
150 5
200 10
300 3
500 0
SCALE
SCALE
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Steps cont.
Amount of Protein (g) Muscle Growth (cm)
150 5
200 10
300 3
500 0

• 4. Plot the data points put a dot on the graph
  for each pair of data in the data table (x, y).
• What are the data points for this data table?
• Sometimes a LINE OF BEST FIT is needed. This
  shows the general relationship between two
  variables in the graph.
• 5. Label the Graph give your graph a title that
  fits the information How Temperature Affects
  Fainting.

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What it Looks Like
2. Label the Axis
5. Label the Graph
1. Draw the Axes.
Population
4. Plot the Data Points
3. Range and Scale
Years
2. Label the Axis
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3 Main Types of Graphs

• Line Graph 3. Pie
  Chart
• 2. Bar Graph

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To Make A Bar Graph

• Follow the same 5 steps.
• EXCEPT For the x-axis there will be no scale.
  The titles on the data table are the titles of
  each bar.

Introductory Courses Enrollment
Chem 150
Phys 120
Econ 350
Poly 250
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Make a scale for each data table

• X- axis
  2. X-axis
• Y axis
  Y-axis

Amount of food Hours of Sleep
2 8
3 10
1 12
5 6
Temperature in Celsius Students who faint in formation
38 20
39 23
40 50
41 100
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Dont forget about variables
Dependent
Independent
Time Distance
1 5
2 7
3 10
4 13

• INDEPENDENT VARIABLE THE VARIABLE THE
• SCIENTIST CHANGES.
• Is always on the left side of the data table
• Is always on the x-axis on the graph (horizontal)
• DEPENDENT VARIABLE THE VARIABLE THAT CHANGES
  BECAUSE THE INDEPENDENT VARIABLE CHANGES
• Is always on the right side of the data table
• Is always on the y-axis of the graph (vertical)

Distance
Time