Calculation of average power using power spectral density.

Hi, I am trying to use the avgpower method to integrate the power spectral density. As mentioned in http://www.mathworks.co.uk/help/signal/ref/dspdata.html

"avgpower(Hs,freqrange) specifies the frequency range over which to calculate the average power. freqrange is a two-element vector of the frequencies between which to calculate. If a frequency value does not match exactly the frequency in Hs, the next closest value is used. Note that the first frequency value in freqrange is included in the calculation and the second value is excluded."

I have two questions

1) Is the frequency range is rad or degrees? 2) As highlighted in bold why is only the first element in the frequency range used?