On Friday, August 26, investors will parse Federal Reserve Chair Janet Yellen's speech at a monetary policy symposium in Jackson Hole, Wyoming. The speech is set to begin at 10am Eastern and the big question is how Yellen frames the timing of the next interest rate hike. Investors are pricing in a 28 percent chance of a liftoff following the Fed's September meeting and a 54 percent probability in December, according to Bloomberg data. Also in focus on Friday, is the second estimate for second quarter gross domestic product, which is expected to rise by 1.1 percent, compared to a previously reported 1.2 percent. In addition, July trade data and August consumer sentiment is released Friday morning. TheStreet's Scott Gamm reports from Wall Street.