Wal-Mart Profit Up, Raises Outlook  NEW YORK (Reuters) - Wal-Mart Stores Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=WMT.N target=/stocks/quickinfo/fullquote"&gt;WMT.N&lt;/A&gt;, the  world's biggest retailer, posted a 13 percent rise in quarterly  profit on Tuesday and raised its outlook and expectations for  holiday sales, saying the economy was improving.