Analyzing chord progressions is a skill you must learn if you want to be a serious guitarist/musician.
Many times in guitar playing you will get chord progressions written out by hand without key signatures or you might learn the song progression from a recording. In either case you need to establish what key or keys you are in to improvise effectively.
Here is the F Scale and the triads that go with it.
All major scales have three major chords and three minor chords. The diminished chord would not be a tonal center chord except in some forms of Jazz or Blues/jazz fusion
Here is the F scale with the 4 note chords that get a lot of use.
The I, IV and V chords are major chords but only the 5th chord(C,C7) can be a dominant chord. So if you see a C7 you are in F major. The I and IV are major 7th chords, a smoother sound.
If you have an F major chord in the progression you could be in the keys of F, B flat or C. If it was an F7 you would be in B flat.
A song for this key that comes to mind is Smooth Operator by Sade. vi-iii-ii-iii or Dm-Am-Gm-Am. The song has a minor tonality even though it’s from the major scale.
Keys and Chords
Suppose you have a progression in which you have two major chords one whole tone apart like B flat to C
The only place this happens in the major scales is the IV and V chord. If you look at the table you will see you are in the key of F major
Only two of the minor chords in the major scale are used as a home base. The ii and the vi. The iii chord produces a minor flat 9 scale which doesn’t sound good
One popular minor progression is the ii-V(two-ive). C it would be Dm to G but usually Dm7 to G7, just extended chords which give more color to the sound.
I hope you found this page useful.