Stock futures were sliding on Friday, ahead of key inflation data that will help investors to figure out if the Federal Reserve will cut interest rates next month. Futures tracking the Dow Jones Industrial Average fell 83 points, or 0.2%, and S&P 500 futures slipped 0.1%. The key event driving markets on Friday is likely to be the release of the personal consumption expenditures price index, which is the Fed’s preferred measure of inflation.