# Comparing Results from an Experiment: What Statistical Measure is Important?

1. Aug 12, 2011

Hi folks

I have an experiment in which I take an image of a flame. I then run a software routine that tells me what the concentrations of OH (hydroxyl) is at different heights above the flame. I first have to give it a calibrated image of a flame with known data and it then is able to give me data about an unknown flame as stated above. Here is what I have done:

1. Give calibrated the software with a known flame image with known data

2. Imaged 2 different flames that are unknown. the software then returns the OH concentrations of these tow flames.

I am curious to know what statistical measures are important? I suppose I should compare the 2 data sets from the unknown flames so I can show that the data sets are statistically similar and not outside of the bounds of experimental error.

2. Aug 13, 2011

### Stephen Tashi

That is a question for combustion engineering, not for for statistics

My observation of human nature (not yours particularly, but from my sampling of forum postings) is that when people are faced with complicated problems involving probability, they avoid the necessary step of figuring out exactly what they are trying to accomplish. Instead of answering that question, they ask what "statistics" says they should do.

Unfortunately, mathematics and statistics don't tell you anything until you know what you are trying to accomplish. To give some completely hypothetical examples, suppose the flame is a flame in the burner of a furnace. Suppose one consideration for such flames is whether they get hot enough to damage the combustion chamber. Then you would be interested whether hot areas of the flame are near the surface of the chamber, how hot they are, how long this lasts. Perhaps physics tells you that a very tiny hot spot that only lasts for a short time won't burn a pinhole in the chamber, so you would want to know the probability that there would be hot spots that would be big enough and last long enough to be dangerous.

You have to figure out what properties of the flame are important from the viewpoint of combustion engineering.

3. Aug 13, 2011