For education and discussion only. Not for commercial use. CHICAGO (Reuters) - U.S. health insurer Cigna Corp. on Friday said it would cut about 9 percent of its work force, or 3,000 jobs, after its membership ranks fell sharply in the fourth quarter, sending its shares tumbling. Cigna, struggling to recover after failing to price premiums in line with skyrocketing medical costs in recent years, posted a fourth-quarter net profit but also said it would slash its quarterly dividend. Analysts said they are skeptical that the company's proposed remedies will improve Cigna's woes with customer service, gauging medical costs, and...