Wall St. drops amid worries over North Korea test, rate outlook

U.S. stocks dropped on Friday, giving the S&P 500 its worst day since June as investor nervousness increased following a nuclear test by North Korea and Federal Reserve officials' comments lifted rate hike bets. The CBOE Volatility index closed at its highest level since late June, while the S&P 500 index closed below its 50-day moving average for the first time also in about two months, a sign that further weakness may be ahead. "With worries about growth and what the Fed is going to do