The essential ingredients of our propaganda model, or set of news “filters,” fall under the following headings: (I) the size, concentrated ownership, owner wealth, and profit orientation of the dominant mass-media firms; (~) advertising as the primary income source of the mass media; (3) the reliance of the media on information provided by government, business, and “experts” funded and approved by these primary sources and agents of power; (4) “flak” as a means of disciplining the media; and (5) “anticommunism” as a national religion and control mechanism. These elements interact with and reinforce one another. The raw material of news must pass through successive filters, leaving only the cleansed residue fit to print. They fix the premises of discourse and interpretation, and the definition of what is newsworthy in the first place, and they explain the basis and operations of what amount to propaganda campaigns.
You can read through their methodologies if interested
https://today.yougov.com/about/panel-methodology
https://www.dataforprogress.org/our-methodology
Public sentiment and public opinions are mostly affected by the rhetoric they hear and lived experience (material conditions).
Rhetoric is certainly wielded to affect public sentiment, if you’re interested in learning more about how, you should read Manufacturing Consent
Manufacturing Consent
https://chomsky.info/consent01/