Mind Monitor

I am now doing a graduation design with the data collected by mind monitor.
I would like to ask
1, why the data I collected sometimes less than 0
2, according to some papers , β/α can reflect the attention of a person, generally is less than 1, when they are paying attention is bigger than 1. But I have collected data for a long time, their value is never bigger than 1
3, I measured the data for 3 minutes, in order to analyze them I took the average value, I do not know if it is meaningful

thank you

Delta Theta Alpha Beta Gamma Beta/Alpha
0.712985849 0.352697154 0.377054609 0.174381786 -0.075774303 0.462484165
0.967995155 0.51973771 0.68166128 0.33949079 -0.112230847 0.498034434
0.534114872 0.047185631 0.63205256 0.334583705 0.071037891 0.529360572
0.680414146 0.316411666 0.566627155 0.30505699 -0.084767882 0.538373404
0.009216257 -0.201237837 0.517876479 -0.023793836 -0.548303141 -0.045945002
0.739948968 0.330375837 0.587632057 0.352631262 -0.057176264 0.600088538

#1 - Negative numbers have no particular significance other than that they are low numbers.
#2/3 - The paper you are referencing is likely using a different FFT calculation on the RAW EEG, resulting in a different range for absolutes. You'd have to check how they did their calculations and then see if it's applicable, or you can calculate absolutes in their way using the RAW-EEG recorded from Mind Monitor.