- #1
nixi
- 2
- 0
Hi I am not sure what method to use when analysing the difference in values between physical measured data and modeled data.
This is to do with measuring the energy deposited at a point in water from a beam of photons.
I have a set of physical measurements obtained whilst varying the position of the measurement point in the water and the parameters of the photon beam. The water and its measurement positions have then been created virtually and the beam parameters have been modeled with various algorithms to produce a similar set of measurements to the physical data.
I assume the data is in independent pairs across the physical + modeled data that I want to analyse the overall difference of, rather than the physical and modeled being sample sets of a parent population. Therefore I have then calculated the difference between each physical and modeled data for the same parameter, but I am getting confused as to how to analyse all the differences together to give me a measure of how well each algorithm replicates the physical data. (the next step will be intercomparisons of the algorithms to see if it is safe to swap to a new one).
I'm not sure that it is a case of just taking the arithemtic mean as some values are positive and some are negative so the mean will surely be skewed? Should I be calculating an absolute mean difference and possibly also a relative mean difference to quantify both the average deviation and the direction of the deviation (over/underestimate)? Until today I have never heard of these averages so am not sure if this would be their intended useage?
How do I then report the error on the appropriate mean to be used in my case? Should I be using an absolute deviation (again new to me, but this seems logical to me) instead of the standard deviation? Or another form of regression analysis? Or maybe some sort of paired difference testing?
Stats isn't my strongest area, and I have just been finding more and more statistical tests today that I know nothing about. If someone could point me to the correct testing for my situation I should be able to use other resources to do the calculations.
Thanks this forum has been a great help over the years,
Nicola
This is to do with measuring the energy deposited at a point in water from a beam of photons.
I have a set of physical measurements obtained whilst varying the position of the measurement point in the water and the parameters of the photon beam. The water and its measurement positions have then been created virtually and the beam parameters have been modeled with various algorithms to produce a similar set of measurements to the physical data.
I assume the data is in independent pairs across the physical + modeled data that I want to analyse the overall difference of, rather than the physical and modeled being sample sets of a parent population. Therefore I have then calculated the difference between each physical and modeled data for the same parameter, but I am getting confused as to how to analyse all the differences together to give me a measure of how well each algorithm replicates the physical data. (the next step will be intercomparisons of the algorithms to see if it is safe to swap to a new one).
I'm not sure that it is a case of just taking the arithemtic mean as some values are positive and some are negative so the mean will surely be skewed? Should I be calculating an absolute mean difference and possibly also a relative mean difference to quantify both the average deviation and the direction of the deviation (over/underestimate)? Until today I have never heard of these averages so am not sure if this would be their intended useage?
How do I then report the error on the appropriate mean to be used in my case? Should I be using an absolute deviation (again new to me, but this seems logical to me) instead of the standard deviation? Or another form of regression analysis? Or maybe some sort of paired difference testing?
Stats isn't my strongest area, and I have just been finding more and more statistical tests today that I know nothing about. If someone could point me to the correct testing for my situation I should be able to use other resources to do the calculations.
Thanks this forum has been a great help over the years,
Nicola
Last edited: