Question

I'm working on exponential regression and have a table that compares student credit card debit each month after graduation. So it goes something like this:
Month 1 2 3 4
Debt $1 $2 $4 $7

(Just put in these numbers for reference, to ask my question)

So the question is -- how much is a student's credit card one year after graduating?

Do I use 12 as the x in the equation y = ab^x, or do I use 13 so I can go all way the through the 12th month?

Thank you.

Answer 1

12
say graduated on Jan 15
first payment Jan 30 , last payment Dec 30