Hey Bitflipper,  there isn't any insulation above my ceiling tiles. I thought about also hanging a panel above my work station, but wasn't sure if I need it.  As far as the insulation in the ceiling, how much of the ceiling would I need to do to be effective?

Was mentioned before but yes, the waterfall helps with seeing the decay at various frequencies.  This is why doing just an EQ adjustment may not completely help.  If anything excites a node at a problem frequency and it's one that rings longer than other, anything in that area will tend to be muddy especially if in the low end.
 
It can be useful viewing the different frequencies with RT60 values (this is the time it takes for an impulse to decay to -60dB)
I found a nice explanation with an ios app video.  Not an endorsement, just a pretty good overview of a type of measurement good for examining room resonances.  There are many out there.
https://www.youtube.com/watch?v=I5clO5fbISI
 
In this particular video I imagine a floor measurement is resulting in more comb filtering than it should :)
So you'd more than likely NOT want to have your measuring microphone right against a wall or floor or in a corner unless you want to measure responses at those locations for some reason.
 
Keith