U.S. stocks closed higher Friday, as investors focused on signs of improvement in the U.S. economy.In U.S. economic news, a measure of consumer sentiment rose to its highest level in nearly six years. Separately, a report on leading economic indicators bounced back in April. In corporate news, J.C. Penney shares slid after the ailing retailer reported another massive loss. Nordstrom shares sank after the company reported weaker-than-expected revenue growth and trimmed its sales outlook. A year after Facebook’s disastrous stock market debut, the social network’s stock is still 30 percent below its IPO price of $38 a share. Shares of Tableau Software surged 60 percent in their debut on the New York Stock Exchange. Shares of Marketo rallied 67 percent in their debut after the business-to-business software firm raised nearly $80 million through an IPO. The dollar rose against the euro, the pound, and the yen. Light sweet crude oil for June delivery gained 86 cents to $96.02 a barrel on the New York Mercantile Exchange. Gold futures fell $22.20 to $1,364.70 an ounce. The Dow Jones industrial average climbed 121.18, or 0.80 percent, to 15,354.40. The broader Standard & Poor’s 500 index gained 15.65, or 0.95 percent, to 1,666.12. The technology-heavy Nasdaq composite index rose 33.73, or 33.73 percent, to 3,498.97