The lingerie company Aerie stopped modifying the photos of its models in an ad campaign that it called Aerie Real. Psychology researchers wondered whether this was just a publicity stunt or whether it could have a positive impact on the women who viewed the ads (Convertino, Rodgers, Franko, & Jodoin, 2016). They randomly assigned 200 women to two groups. One group saw photos of Aerie models that were digitally modified, and a second group saw photos from the new Aerie Real campaign. All participants then completed the Body Image State Scale, which includes six questions that participants rate on a scale of 1–9. Overall, the researchers did not find a statistically significant difference between the two groups (although they did find a positive effect of the Aerie Real campaign among women who were more focused on physical appearances). What statistical test might they have used?