GMAT Strategy

For an MGMAT 650, yes.

Although remember that standard deviation just means you are most likely between 600-700, not definitely. Technically, it means you have a 2/3 chance of being between 600-700 and a 1/3 chance of being below or above that range.

A lot of people think that our individual math qustions are a bit harder than the real test, but that is by no means universal. It's not unusual for people to get into timing problems on the math section and then they can really underperform. (We're trying to combat this by forcing you to figure out how to work with your timing on our tests - the fact that they're so hard means you have to figure out how to deal with timing ahead of time.)

Potentially, yes. It depends on the mix of experimental questions and what range you were in right before you had a string of wrong answers.

Your MGMAT tests are all within the 650 range; remember that our tests have a standard deviation of about 50 points (compared to about 30 points for the official test).

In terms of how to improve, you're really going to have to diagnose your strengths and weaknesses. Have you been running the test reports on your MGMAT tests? If not, do that and start making a list of the areas in which you either aren't getting enough right or you're taking too long. Go back and look at the individual questions and figure out what caused you to get that question wrong, spend too much time, or whatever. You really need to pick apart and analyze your performance.

Do pay attention to areas in which you think you're weak, of course - chances are you're right. But do the above analysis so you can actually see, via the hard data, what your strengths and weaknesses are.

Could you, yes - you're in the right range. (That doesn't mean you absolutely will, of course.)

I always tell everyone to assume they'll take it twice, just in case. So go into the first test assuming that this is just the dry run.

You're right in the range, so you may want to go ahead and take it to see if you get your score. The experience will give you a good idea of what to improve if you have to take it again.

Have you taken an official test before? The schools take the higher score, and most don't care if you take it 2 or 3 times, so as long as you'd be within that parameter, it's not a big deal to have taken it multiple times.

Re: improving in verbal, you need to know very specifically what your weaknesses are, across grammar rules for SC and question types for the other two. You can't improve if you don't know what you need to improve.

I'm not familiar with the Kaplan book, so I'll leave that for someone who has used it.

You need to go and figure out why you made the mistakes you made for verbal. For every single question - go figure out why you fell into the trap of picking the wrong answer and why you thought the right answer was wrong. That's the only way to learn how NOT to fall into those same traps again.