Gaseous system: Meaning of this integral eq.

[jam_27]

What is the physical or statistical meaning of the following integral

\int^{a}_{o} g(\vartheta) d(\vartheta) = \int^{\infty}_{a} g(\vartheta) d(\vartheta)

where g(\vartheta) is a Gaussian in \vartheta describing the transition frequency fluctuation in a gaseous system (assume two-level and inhomogeneous) .

\vartheta = \omega_{0} -\omega, where \omega_{0} is the peak frequency and \omega the running frequency.

I understand that the integral finds a point \vartheta = a for which the area under the curve (the Gaussian) between 0 to a and a to \infty are equal.

But is there a statistical meaning to this integral? Does it find something like the most-probable value \vartheta = a? But the most probable value should be \vartheta = 0 in my understanding! So what does the point \vartheta = a tell us?

I will be grateful if somebody can explain this and/or direct me to a reference.

Cheers

Jamy

 

[azntoon]

angThe integral in question is a type of probability distribution known as a Gaussian or normal distribution. This type of distribution is used to describe the probability of a certain event occurring. In this case, the integral is computing the probability of the transition frequency fluctuation in a gaseous system taking on a particular value (in this case, \vartheta = a). The integral finds a point \vartheta = a for which the area under the curve (the Gaussian) between 0 to a and a to \infty are equal. This is the most probable value of \vartheta - i.e. the value that is most likely to be observed.