After 19 years covering the stock market for USA TODAY, Adam Shell gives his best advice on how to successfully invest in the market. USA TODAY

Stock finished lower Friday after a disappointing February jobs report that capped a week of losses for the markets. Investors remain concerned about a global economic slowdown following a string of downbeat news.

The Dow Jones Industrial average slipped 23 points, or 0.09 percent, to end at 25,450 on Friday. Its five-day decline this week marked its longest losing streak since June.

The Standard & Poor’s 500