What is being tested in each section?
The Analysis of an Argument Section tests your ability to evaluate an argument, think critically and communicate your positions. You will be provided with an argument and given 30 minutes to write an essay on the merits and flaws of that argument. A sample question can be found here.
The Integrated Reasoning Section tests your ability to evaluate data from different sources and platforms. You will be given a total of 12 different questions, some of which will have multiple parts. There are four different types of questions: multi-source reasoning, two part analysis, table analysis and graphics interpretation. Sample questions for all different types can be found here.
The Quantitative Section tests your reasoning skills. You will need to understand basic mathematics, including: fractions, decimals, percents, combinatorics, geometry, algebra and number properties. There are a total of 37 multiple choice questions, which will be either data sufficiency or problem solving.
The Verbal Section tests your skills in grammar, reading comprehension and critical thinking skills. There are a total of 41 questions that will come in the form of either sentence correction, critical reasoning or reading comprehension.
How is each section scored and what does that score mean to business schools?
Your total (and most important) score is on a scale from 200-800, and is based off your Verbal and Quantitative scores, which are individually scored on a scale from 0-60.
The Analysis of an Argument section is scored on a scale of 0-6 (in half point intervals). All business schools want to glean from this section of the test is that you are capable of the kind of writing business schools require. Therefore, any score above a 4 is usually satisfactory.
The Integrated Reasoning Section was added to the test in 2012 and is scored from 1-8. Since it is so new, it is still unclear exactly how it factors into the admissions process, so just do the best you can without stressing too much about it. The good news is that skills it tests are very similar to those tested in the quantitative and verbal section, so it is not a lot of new learning.