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Statistical assessment of the quality of event detention

  1. Jan 2, 2014 #1

    I developed an algorithm to detect events in time domain and I want to know the efficiency of the algorithm.

    The problem is related with the time duration of the data.

    Each file has data with a time duration of hundreds of minutes and I have dozens of files.

    Instead of calculate the specificity and the sensitivity of this algorithm for the entire data set, I was thinking to choose random samples.

    My question is:

    What is the correct approach to have a valid statistical analysis?

    Thank you.
  2. jcsd
  3. Jan 2, 2014 #2

    Stephen Tashi

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    Unfortunately, applications of statistics involve subjective judgements. If you want practical advice about a valid statistical approach, you need to give more practical details of the situation. For example, what are you concerned about? - the number of events in the file? - the exact time when an event occurs? Do you have information about when an event "really" happened vs when the algorithm said it happened?
  4. Jan 6, 2014 #3
    I am studying sounds in time domain. Usually this sound has a low amplitude profile, just noise. Sometimes, a sound is generated and there is an increase in the signal amplitude.

    The goal of the algorithm is to detect this increase in the signal amplitude. Unfortunately, the generation of a sound can be interpreted as random. It is possible that a low amplitude profile lasts for minutes or even hours without a single sound being generated. On the other hand, it is possible that there is a sequence of sounds for several minutes with a time difference between the sound n+1 and the sound n of just a few seconds.

    I am concerned with the quality of the detection, sensitivity and specificity. This means a desire of knowing if a generated sound is either detected or not detected and if there is a "detected" sound when no sound is generated.

    I do not have any prior information, just the one given by the algorithm.

    Thank you
  5. Jan 6, 2014 #4

    Stephen Tashi

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    Science Advisor

    If that means that you have no way to compare the detections from the algorithm to real events then I think you should resort to simulating data from "real" events and seeing how well the algorithm detects them. To simulate data from events, you need algorithms to do the simulation.

    If you want to do statistical hypothesis testing on each set of data, you need a "null hypothesis", which could be that no sounds are present and that the data is generated by some specific random process. You need a way to compute the probability of getting similar data when those assumptions are true. If you have no algorithm or formula to compute this probability then you can't do hypothesis testing.

    There may be situations in engineering and science where people have developed standard methods of dealing with your problem. You can try asking about your problem in the engineering or science sections of the forum and give more details.
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