Looking at the source material:

Objective

Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty). This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites.
So they've already made a decision, and want to see if it's true. Going into the study with an end result already in mind directs how it goes, and will influence the results. They also limit the study to only Caucasian people.