When designing an experiment, you can go a few different ways.
If you want to improve a system or method, you can question every step in a process and ask, "Why is this factor set at this level? Why do we do this step?" Let's just say there is a reason why LEAN and 6 sigma are popular in industry.
You can say, "These might be realistic levels for an natural system. Let's see what happens when we start making these changes...."
You can say, "I want to make Product W and start with materials X, Y and Z. Let's see what happens."
In science, you tend to develop theory from data. You change your theory when new data contradicts the theory. You might go into an experiment thinking there are some sort of relationships. You might just be interested to see what happens when....
Let's be honest. If you found some relationships that are very predictive but have no theoretical basis, and you can:
1) Make lots of money
2) Save lots of lives
3) Live better
You'll use those relationships. You can develop the theory later. Until then, knowing that under a certain set of conditions, some event will occur IS the important part. Remember, science starts with data then goes to theory. Data=> Theory=> (Better data => Better Theory)
NAlso consider that, if someone is a subject matter expert and they already know what will happen with 100% certainty, then there is NO POINT in doing an experiment. The is NO NEED for statistics nor data science.... and there is no hole in the ozone layer.
Until then, spurious correlations, odd relationships and "Hhhmmmm. That's interesting." will rule science and we will need statistics and data science to feed that curiosity. We will need statistics to help determine if an effect is "real" or "probably nothing". We will need data science to go through all the data to find those correlations and relationships.
If you don't think so, ask yourself this, "Would someone from 10, 20, 50, 100, 200, 500, 1,000 years ago feel the results I have are consistent with their thinking/theory?" or "Where did the theories I use today come from?"
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Andrew Ekstrom
Statistician, Chemist, HPC Abuser;-)
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Original Message:
Sent: 12-16-2017 03:23
From: Thomas Davis
Subject: Defining Data Science
Cheng and Andrew,
Use of statistics for prediction, decision, or any inference depends on some model, which hopeably is based on some understanding of the context. A well known statistician, I don't recall which one, I think he was Bayesian, once pointed out that all inference is conditional on the model.
Of course, predictions and decisions can be made statistically without hypothesis testing. On the other hand, hypothesis testing has been cast in terms of statistical decision theory. I currently have much sympathy for the view that statistical theory is statistical decision theory. There are, of course, statisticians who disagree with this approach.
But I think my real point is not to confuse any of this conceptually with theories in science, although there rightly is overlap in practice.
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Thomas M. Davis
Original Message:
Sent: 12-15-2017 10:36
From: Cheng Cheng
Subject: Defining Data Science
The point is can a prediction or a decision generated without understanding any relationship or association be trustworthy.
A substantial portion of scientific studies do not have a theory, in fact they generate theory from properly, effectively, and efficiently exploring the data (to do a data exploration well requires some study design too); and the so generated theory is then tested with further experiments.
I do not work with toxicologists bur I work with pharmacogenomics investigators who routinely study chemo toxicities a great deal, where drug-drug, drug-host interactions are always critical factors, which are handled by proper experimental designs and statistical modeling. Sometimes, discovering interactions is the goal of the study. "Everybody knows you can't change more than [one] thing at a time..." was already outdated when I was in grad school.
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Original Message------
For a great deal of science, there often is no theory or the theory is just plain wrong.
Let's take toxicology for example. Toxicologists don't test for interactions among medications because they believe the interactions don't occur or you can't test for them. Most of their theories assume Design of Experiments doesn't exist because "Everybody knows you can't change more than thing at a time..." Thus you never see warnings on your meds.. oh wait, you do.
If you require theory to determine if some effect is real, especially if it's not straight forward, people will die. People have died because no theory existed.
Some things to think about; Use theory (at the time) to prove
1) Mold is an anti-biotic. (Penicillin)
2) There's a hole in the Ozone layer.
3) Why we sleep.
4) How does coffee work.
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Andrew Ekstrom
Statistician, Chemist, HPC Abuser;-)
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