Wall Street set to open lower as rate hike timing regains focus

Wall Street looked set to open lower on Friday after a week of choppy trading as the corporate earnings season winds down and investors again focus on the timing of the Federal Reserve's next interest rate hike. Investors were also cagey ahead of next week's annual meeting of central bankers from around the world in Jackson Hole, Wyoming, in which Fed Chair Janet Yellen is likely to cement expectations for a slow pace of rate increases. Recent hawkish comments from two Fed officials have clashed