Calculation of Bass Ratio in a Room

Reverberation Time at 125 Hz octave band (in sec):
Reverberation Time at 250 Hz octave band (in sec):
Reverberation Time at 500 Hz octave band (in sec):
Reverberation Time at 1000 Hz octave band (in sec):

Average RT from 125 Hz to 1000 Hz = sec
Bass Ratio =
This is for a room with this average reverberation time.