What is the test for establishing a hostile work environment claim?

A plaintiff pursuing a hostile work environment claim must establish a basis, rooted in common law agency principles, on which to hold an employer liable for the conduct of its employees. See Meritor Sav. Bank, FSB v. Vinson, 477 U.S. 57, 72, 106 S.Ct. 2399, 2408, 91 L.Ed.2d 49 (1986). This predicate can be established if