WASHINGTON (AP) — President Joe Biden has installed an energetic critic of Big Tech as a top federal regulator at a time when the industry is under intense pressure from Congress, regulators and state attorneys general. The selection of legal scholar Lina Khan to head the Federal Trade Commission is seen as signaling as tough stance toward tech giants Facebook, Google, Amazon and Apple. Khan was sworn in as FTC chair Tuesday just hours after the Senate confirmed her nomination as a commissioner. She helped lay the foundation for a new way of looking at antitrust law beyond the impact of big-company market dominance on consumer prices.