Importance of Statistics in Scientific Researchcourse1.winona.edu/cmalone/Promotion/Presentations/Importance o… · International Science and Engineering Fair May 10, 2010 Example

International Science and Engineering FairMay 10, 2010

Thoughts ExamplesExample 1 Q & A

Importance of Statistics in Scientific Research

Christopher J. Malone, PhDWinona State University, Winona, MNEmail: [email protected]


Thoughts ExamplesExample 1 Q & AExample 1

The Hypothesis



The Hypothesis

Force



The Hypothesis

Force

Oops, backwards



The Hypothesis

ForceHigh School Project



The Hypothesis

ForceTheory

High School Project



The Experiment





The Experiment



The Experiment



The Experiment



The Experiment

Forcemass speed



The Experiment

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The Experiment

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Slush is most

dangerous



The Experiment

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Slush is most

dangerousRight?



The Experiment

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15904390 * 4380

2nd Trial



The Experiment

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15904390 * 4380

2nd Trial

Yea, but



HollywoodVersion

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Measurements

Thoughts

› Measurement details should be in research plan › What are you going to measure?› How are you going to measure?

› Measurement issues go beyond identification of independent and dependent variables

› Outcomes must be measurablee.g. “I will identify the day the plant wilts” is not

precise; carefully measuring soil moisture over time is much better



Measurements

Thoughts

› Numerical measurements are generally better than categorical measurements; however, avoid changing data types

Categorical Now, numerical



Measurements

Thoughts

› Numerical measurements are generally better than categorical measurements; however, avoid changing data types

› Why? Averages, Standard Deviations, Correlations, etc.

Categorical Now, numerical



Measurements

Thoughts

› Comparing Averages…

Averages0.670.50



Measurements

Thoughts

› Comparing Averages…

Averages0.670.50

0.000.50



Measurements

Thoughts

› Measurement issues/concerns are often overlooked› The necessity of precision in measurements cannot be

overstated



Measurements

Thoughts

› Measurement issues/concerns are often overlooked› The necessity of precision in measurements cannot be

overstated

› _



Replication

Thoughts

› Generally speaking, more is better› May be necessary to balance replication and precision



Replication

Thoughts


› How good is my shot?



Replication

Thoughts





Replication

Thoughts





Replication

Thoughts


› Replication allows us to estimate the error due to variables that are not under our control (i.e. noise)



Replication

Thoughts



› Which in turn allows us to measure and possibly attribute an observed outcome to the variables that areunder our control (i.e. effect)



Replication

Thoughts



› Which in turn allows us to measure and possibly attribute an observed outcome to the variables that areunder our control (i.e. effect)

› _



Summaries and Displays

Thoughts

› Usually inappropriate to display raw data, especially for high school projects




Thoughts





Thoughts


› Bar charts should only be used for tallys, not for numerical measurements (including averages)




Thoughts

› Bar charts should only be used for tally’s, not for numerical measurements (including averages)




Thoughts


› Bar charts should only be used for tally’s, not for numerical measurements (including averages)

› Bring back the dot plots! › Simple to construct and easy to read› Stack them to compare groups




Thoughts

› Bring back the dot plots!




Thoughts





Thoughts


Adding Averages, v 1 Adding Averages, v 2




Thoughts

› Generally speaking…› Excel is less than optimal for constructing displays› Numerical data require numerical data displays

› Compute change for paired measurements




Thoughts

› Generally speaking…› Excel is less than optimal for constructing displays› Numerical data require displays for numerical data

› Compute change for paired measurements




Thoughts


› Compute change for paired measurements› % change may be necessary at times

› Scatter plots tend to be under utilized




Thoughts


› Compute change for paired measurements› % change may be necessary at times

› Scatter plots tend to be under utilized

Your summaries and displays should support your story.




Thoughts

› _

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The Statistical Chapter of your Story

Thoughts

› These elements will give statistics an opportunity to help tell your story› Good experimental design techniques› The collection of precise and error free

measurements› The use of appropriate statistical methods› Interpretations that are meaningful and given within

context




Thoughts

› Borrow ideas and concepts from others › e. g. Marketing› e. g. What are the important elements of an

effective persuasive speech? -Learn from Jack Franchetti @ 10:00AM tomorrow…




Thoughts

› Borrow ideas and concepts from others › e. g. Marketing› e. g. What are the important elements of an

effective persuasive speech? -Learn from Jack Franchetti @ 10:00AM tomorrow…

› In the end, your story may be different than your original hypothesis.

› Many of the young scientists here are not presenting their original hypothesis.

› This is indeed the essence of the scientific method!



› Compliments of Wendy Greenberg, Biology Department, Bemidji State University

› Set-up: 1. Play game 5 times with sound,

then 5 times without sound2. Measurement: Score3. Issues???

Examples

Example #1 (Video Games and Sound)



› Compliments of Wendy Greenberg, Biology Department Bemidji State University

› Set-up: 1. Play game 5 times with sound,

then 5 times without sound2. Measurement: Score3. Issues???

Note: Student recognized issue of potential improvement due to learning, but his solution was to switch the order!

Examples

Example #1 (Video Games and Sound)


Thoughts ExamplesExample 1 Q & AExamples

Example #2 (Influencing the color of a flower)› My hypothesis: Does colored water change the color of a

flower?

› Set-up: 1. What should I measure?2. The type of flower is irrelevant to me, but I will use a

rose and tulip for my experiment. 3. Do I need a control? Why or why not?4. I have room for 16 planting pots in my lab.



Example #2 (Influencing the color of a flower)› Sketching an appropriate randomization plan



Example #2 (Influencing the color of a flower)› The Data



Example #2 (Influencing the color of a flower)› The averages


Thoughts ExamplesExample 1 Q & AQ & A

Q & A Session


Thoughts ExamplesExample 1 Q & AQ & A

Thank you!

Chris MaloneWinona State University

Email: [email protected]

Documents

Importance of Statistics in Scientific Researchcourse1.winona.edu/cmalone/Promotion/Presentations/Importance o… · International Science and Engineering Fair May 10, 2010 Example