Champ Tier and Star understanding

So in terms of power, is 9x 1* the same as a 1x 3* unit?

If I had 9 different T1 & 1* units (assuming no synergy & items) is that going to have the same power as a ... 3* Garen?

I understand that the higher the champ tiers the stronger they are, but how strong are they?

Is T5 unit (ASol) the same as 5xT1?