Wall Street set to open lower as oil prices drop

With the earnings season coming to an end, investor focus will shift to Federal Reserve Chair Janet Yellen's speech on Friday at the annual central bankers' meeting in Jackson Hole, Wyoming. "The markets will start to get a little bit nervous about what's going to be said, what kind of indications will be given about a September hike," said Robert Pavlik, chief market strategist at Boston Private Wealth in New York. The case for an imminent rate hike was strengthened by Fed Vice Chairman Stanley