Practice figuring out whether we took a random sample and whether we're able to draw valid conclusions from our data.

Problem

An ad for Snow White Toothpaste states, "9 out of 10 dentists recommend Snow White for a whiter smile." No information is given about how the company obtained its data.
Based on this data, which of the following conclusions are valid?
Select all that apply.
    Select all that apply.
Get 5 answers correct in a row