Spectrum for all bands in a ROI

Is there a way to calculate the average value of each band for a ROI (with statistics)?
Similar to Spectrum View but instead of for a single pixel for the whole ROI.
A similiar option exists in ENVI


In the Statistics View you can select an ROI. But only for a single band, unfortunately.

On the command line, you could use the StatisticsOp.
In this thread, you can find more information: A StatisticsOp graph