Question: The number of people responding to a mailed information brochure on cruises of the Royal Viking Line through an agency in San Francisco is approximately normally distributed. The agency found that 10% of the time, over 1,000 people respond immediately after a mailing, and 50% of the time, at least 650 people respond right after the mailing. Find the mean and the standard deviation of the number of people who respond following a mailing.