## Averaging Amplitudes of Different Frequency Bands

Trigonometric ratios and functions, the unit circle, inverse trig functions, identities, trig graphs, etc.
tsguigna
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### Averaging Amplitudes of Different Frequency Bands

Hello everyone! I am in a pickle right now as I attempt to move forward in my research project on neurofeedback. I am trying to calculate the theta/beta ratio for individual subjects and then compare them statistically. The issue I am having is statistically comparing amplitudes of different frequency bands. For example, in the theta category, I have a subject that had his/her frequency range of 2-9 Hz inhibited. For another subject, his/her frequency range of 3-6 Hz was inhibited. I cannot compare the average amplitudes of these two subjects because the wider a frequency band is, the larger the amplitude is (generally). Basically, for the first subject, what would his/her amplitude be if I restricted the bandwidth from 2-9 Hz to 3-6 Hz? The amplitude for the 2-9Hz range is 34.3, so how much would the amplitude decrease by if I restricted that subject's frequency range to 3-6 Hz? Let me know if this issue is not clear and I will try to adjust my question. Thanks everybody!

maggiemagnet
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### Re: Averaging Amplitudes of Different Frequency Bands

Hello everyone! I am in a pickle right now as I attempt to move forward in my research project on neurofeedback. I am trying to calculate the theta/beta ratio for individual subjects and then compare them statistically.
Are you talking about brain waves, like they show here?
The issue I am having is statistically comparing amplitudes of different frequency bands. For example, in the theta category, I have a subject that had his/her frequency range of 2-9 Hz inhibited. For another subject, his/her frequency range of 3-6 Hz was inhibited. I cannot compare the average amplitudes of these two subjects because the wider a frequency band is, the larger the amplitude is (generally). Basically, for the first subject, what would his/her amplitude be if I restricted the bandwidth from 2-9 Hz to 3-6 Hz?
How do you know that this sort of re-setting (of the measurements from one "band" to another) is valid? (I'm not a neuroscientist, so I have no idea what the science is behind whatever you're talking about.) What sort of "statistical comparison" are you needing to do, exactly? What do you mean by "inhibited"? If the "band" in which the "range" is inhibited matters, then how would new results, which pretend that the "range" was something else, still be valid?

Please remember that we only know some math. Applications (like physics or engineering) involve "real life" (with specific models, assumptions, variables, constants, etc) whose relation to the math need to be specified. For instance, we can help with variation equations, but would need an explanation of, say, a gravity-mass-weight formula, along with specifications of constants, before being able to help a student figure out his "weight" on a fictional planet orbiting some distant start. For your exercise, you'll have to explain the underlying science, and specify exactly what you're trying to do with the math, before math-y folks can probably have much of anything to say. (For instance, a neurofeedback professional here seems to think that mathematics is not relevant; you need to do something with the recording and processing software, I think, as relates to the raw data.) Thank you!