Few Business Owners Seem to Even Know How to Make a Good Guess at What Their Business is Worth.  NY Times Introduces Technology to Help—and Certified Advisers Provide Extra Value.  Mark Cohen, at The New York Times Small Business Guide, reports:  “At 53, Joe Ritz is old enough to remember a time when many of the classic cars that now pull into his specialized repair shop were new. “It’s one field where it pays to be a senior citizen,” he said. It’s Critical for a Business Owner to Know the Value of His Business; Here are Tips on Technology, Advisors,…