Methodology
I first began by developing my null and alternate hypotheses:
Because we are testing the means of 2 sample groups that are fairly normally distributed (see Figure 1), I chose to run a version of the unpaired t test. This was chosen over a Z test since the type of data is parametric. After further data exploration, I found that the variances were not homogeneous, so I narrowed down the test to a Welch's t Test (as opposed to a normal unpaired t).