1. UNLOCKING THE SECRETS HIDDEN IN YOUR DATA
Data Analysis
UNLOCKING THE SECRETS HIDDEN IN YOUR DATA

2. Why Do Data Analysis ? Avoids incorrect assumptions
Does the data makes sense?
Which one is better?

3. Why Do Data Analysis ? Are your assumptions correct?
Did you collect enough data?
If this is a model of a following body which is better?
Be careful what's better mathematically is not always better scientifically

4. Ways to Analyze Data Plotting Data Statistics
Ways to visually understand data
Statistics
Makes is easier to compare data
Mean, Median, Mode
Makes it clear if you have NOISY data
Range, Variance, Standard Deviation

5. Ways to Analyze Data Derivatives (Slopes)
Tell if changes in parameters affect data
Parameter 2 has a greater effect than Parameter 1
Get more information from data
Great
Derivative
Slope = 0.39
Slope = 0.16
Slope = 0.08

6. Plotting Data – Extracting from Netlogo
Two ways
1st Way: Write code to extract the data you want – see File Output Example in the Code Examples
Open file in setup procedure
Create a write-to-file procedure

7. Plotting Data – Extracting from Netlogo
2nd way: Extract data from Netlogo graphs
Have Netlogo generate graph on Interface page (example on later slide)
Create a setup-plot procedure and a do-plot procedure
Call the setup-plot procedure in setup procedure
Call do-plot procedure in go procedure

8. Plotting Data – Extracting from Netlogo
Run model until sufficient data obtained
(PC) Right Click on Graph/(Mac)
Select Export
Choose location and File name - select save
Excel File is created – Next Slide
Contains all the information in the plot and input parameters used.
Contains excess information about the plot (color, pen down, mode, interval…)
LET’S DO IT – Open Rabbits Grass Weeds

9. Plotting Data – Extracting from Netlogo
This is what
You need

10. Plotting Data – Different Types of Plots All plots from http://www
Bar Charts – preferred snacks
Pie Charts – music preference
Pets purchased at pet store

11. Plotting Data – Different Types of Plots All plots from http://www
Line Graphs – cell phone use
Scatter Plots

12. Plotting Data – Activity in Excel
LET’S DO IT
Open File Car Data
Insert Chart
Select type of chart
XY Scatter
Select Data Range
Highlight data to be plotted

13. Plotting Data – Activity in Excel
Label each data series
Label Graph and Axis
Select where you want graph to be (on that page -worksheet –or on another worksheet in same file)

14. Statistics Statistics help you Summarize data Describe data
Analyze data
Now it is easy to summarize, describe
and analyze the data….
The blue and the pink data have the
AVERAGE value (mean) but the blue
data is “NOISIER” (greater standard
deviation). Therefore…
Hard to describe the difference
Between the two data sets

15. Statistics – How to Calculate in Excel
+,-,*,/ used for addition, subtraction, multiplication and division.
Each cell has a label based on the column and row.
Use cells to perform calculations instead of numbers. Example : =(A4+B4)/C4
Perform calculations on an entire column - copy and paste the equation .Warning : this changes the cell number for each line.
Fix a specific cell - use the $ symbol, example (A4+B4)/$C$1
Excel has many built in statistical functions
Makes life easy! E1

16. Statistics – Measurements of Central Tendency Mean (Average), Median, and Mode
Definitions
Mean (Average) – Sum divided by the number of data points
Median – Middle data point when arranged from highest to lowest
Mode – Most frequent value
Use data set to calculate Mean (Average) Median, Mode, Max and Min
Select Cell where you want the value of the function to appear
Select Insert then Function
Select Statistical
Select function wanted (AVERAGE, MEDIAN, or MODE) then hit OK
Select Range of data you want to analyze by clicking on range symbol and highlighting range. Hit enter or OK
LET’S DO IT : StarlogoTNG : Fish and Plankton
Netlogo : Rabbits and Grass

17. Statistics – Measurements of Data Spread Range, Variance and Standard Deviation
Definitions
Range = maximum - minimum
Variance = measures noise of the data around the mean value.
Standard Deviation (S) is the square
root of the variance. Most commonly
used measure of spread (same units
as the data). Another reason to use S:
~68% of the data are in the interval
Mean – S to Mean + S
~95% of the data are in the interval
Mean – 2 S to Mean + 2 S
~99% of the data are in the interval
Mean – 3 S to Mean + 3 S
EXCEL does it for you!!!
LET’S DO IT : StarlogoTNG : Fish and Plankton
Netlogo : Rabbits and Grass

18. Derivatives What are Derivatives? Why use Derivatives?
A simple calculation using data
Instantaneous rate of change
= SLOPE
Why use Derivatives?
Get more information from data
More Ways to comparison data
Car moving down a road
Data = the distance traveled
Velocity = the 1st derivative
of distance
Acceleration = 2nd derivative of distance
= the 1st derivative of velocity
Slope of distance
Slope of velocity

19. How to Calculate a Derivative
Mathematically:
x = position
t = time
In Excel
You
Don’t
Have
To Use
This
Use
this in
Excel
LET’S DO IT : StarlogoTNG : Fish and Plankton
Netlogo : Rabbits and Grass