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Impartial Data

Data Analysis Fundamentals

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Discussion and questions related to the course Data Analysis Fundamentals

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In the introductionary video, I feel that there was a heavy emphasis that data is impartial.

However, looking at online forums, it seems that sensors from different compagnies output different results (albeit close to one another).

Not sure if it's covered in the rest of the course, but I thought it would be important to mention that you can never truly trust data as absolute truth.

The raw DATA is impartial, the means of gaining it may have an inherent bias that has to be corrected to interpret the data correctly.

It's a good point, though, as many will take the view that it is 'right', regardless.

There are some things one may be able to do to check for one's self with basic equipment, such as 0and 100C (at sea level, as altitude increases the boiling point will drop and there are charts available for this), airports will have very precise air pressure metering equipement or you can often get it from the metrology office, with a long hose, and some water, one can even get a close value for pressure and vacuum - or much shorter hose if one has access to mercury and the sensor is sealed.

It's a fair point you bring up Ali, although I have a different perspective on this. I would argue that what the logger records is impartial, it's really down to the setup and calibration of the sensors, as Gord says. In my experience, the setup and calibration are far more significant than the difference between different sensor brands, for example.

Still, fair point. It's something you need to consider.

Just be mindful of things like signal aliasing, if you are trying to observe intake pressure waves for instance, you really should be logging at 10 times or higher frequency. People can make incorrect inferences about system behaviours if they don't know what they are looking at.

When we're talking about detailed powertrain analysis, damping etc it's true that logging at high frequencies, signal processing and sensor lag become important to consider. In my original answer, I was thinking more from a driver inputs and technique perspective which is what the course really focusses on, where the required logging frequencies are pretty low, relatively speaking anyway 🙂. Good points to bring up though Michael.