Each Track has Live Output Meters in the Track Header.
Also do go: View > Window > Mixing Console . The Mixing Console has heaps of the same Meters but aligned Vertically together and is a real assist to what you want. I use it all the time.
As to an Average, which I don’t understand, but if you mean that which you wish to see just how the audio develops overtime you can see Peaks which you can set.
There are plenty of tools to use in Vegas to do what you want.
Also, as a crude visual, use the Audio Sound File Graphs.
* Grazie
Video Content Creator and Potter
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