If I am talking about where I am physically, would I use ser or estar?
You would use estar. Estar is used as a condition - it is something that can change. You could be at the mall (estoy en el centro comercial) one moment, but be at the gym the next moment. Ser is used for things that do not change so conditionally. For example, if you are a female with blonde hair, you would use ser to describe that (yo soy rubia), since your hair color, theoretically, does not fluctuate.
What is the difference between real and nominal GDP?
Nominal GDP is GDP that has not been adjusted for inflation. It is the actual dollar value of GDP in current dollars (or any currency.) Real GDP is adjusted for inflation so that it presents a number that can be used as a fair comparison to GDP in other years. The equation looks like this: nominal = real + inflation.
How do I prepare for an interview?
I would categorize your preparation into two buckets: tactical and conceptual. Tactical: These are the things you just have to "do." Print out your resume if you have one, dress in something comfortable yet professional, and learn the name and background of your interviewer. Conceptual: This is the preparation for the content of your interview. Prepare answers for sample interview questions, such as "Why do you want to attend X school?" "What have you done in high school that you are most proud of?" "When have you faced adversity, and how did you overcome it.?" When you tell your stories, explain the situation, your role, and the outcome. Let your passion and enthusiasm show. I like to think of one headline that I want the interviewer to remember about me, as a way to stand out. You could be the "athlete with a passion for service" or the "dancer who loves geopolitics," Find your thing - what makes you, you - and let your interviewer know. And of course - smile, relax, and be yourself!