Wow thanks for the detailed response!
The map attached is a rough draft. I included the schools just because I forgot to turn off the layer when I exported the map.
Survey locations were not picked, we contacted all retailers and 16 chose not to participate in the survey.
The only evidence that can indicated that these locations would not be different from closest surveyed locations or other surveyed locations is by understanding the survey data better. For example if our data exploration reviles that store type is the main factor that affects advertising, we can classify the not surveyed by store type and see if they are represented in the surveyed locations.