Ranked is filled with people, who shouldn't be level 30.
Level 30 = You've played about 200-300 games I think, could be even less.
And win amount doesn't neither mean that the player is good: 1300 wins? Okay, but he also has +1100 losses most likely.
A guy with only 500 wins could actually be better than the previous guy since 500 win-guy has only 200 losses. Game amount is much different yes, but I wouldn't be surprised if the latter guy beats the first one.
Also to new LoL.ers:
Learn to last hit.It isn't hard, and it isn't a thing just the pros do or should do. Everyone should know how to last hit. Here is why:
if you use AoE abilities to push the wave, you most likely get the minions die quick but do you get the gold? Maybe not. At 30 minutes if you have 50 minion kills more than usual, it is worth +1000 gold. Sure, because you didn't autoattack the enemy tower has 100 hp more than it does if you'd autoattack, but with those +1000 gold you can buy something to make the pushing even easier.
Also, don't rely on mias. Some people don't call them at all or forget to say them sometimes. Keep watching the minimap every now and then, possibly press TAB and see which enemies are grey: they are missing and possibly ganking you.