Stats against simple data - but need help still

#1
This i my first post...I'm struggling at the moment with a course I'm taking and could use some help. So, here goes!

Here are the details:

Hypothesis: A score on the LSAT below 145 will yield a cumulative GPA of less than a 3.0 in the first year of Law School.

Null: The LSAT score has no affect on a student's first semester GPA

Independent Variable: LSAT Score
Dependent Variable: GPA at the end of the first semester.

I have 2 samples of 100 each. I'm not (and cannot) give the full dataset but here is basically what the data looks like in my Excel spreadsheet:

LSAT Score GPA after 1 semester
130 2.78
156 3.00
155 2.96
141 3.22
140 2.56

This may sound like a dumb question, but how, based on my two samples, do I find out if my hypothesis is true? That students who score less than a 450 on the LSAT will have a GPA lower than a 3.0 after the first semester of law school. I've rad about Chi Square and T-tests and ANOVA etc but I cannot link those tests to proving my hypothesis (or rejecting the null).

Thanks in advance!!!!
 
#2
As this is trying to say something between two things, we might think of this as ' how they are related, are they highly correlated?' One thought will be to try simple regression analysis. GPA=a+b*LSAT, then

H0: b=0

It's possible to try other models, which should desired to be a good conceptualization of the real phenomenon.