Berger and colleagues (2011) conducted a telephone survey of energy drink consumption and alcohol use among adults in Milwaukee. In the method section of their article, they explain that "the study sample was comprised of individuals aged 18 or older who participated in the 2008 Greater Milwaukee Survey, a semiannual cross-sectional random-digit-dial landline telephone survey of household residents in the Milwaukee, Wisconsin Metropolitan Statistical Area. In total, 946 adults aged 18 to 92 participated in the survey for a response rate . . . of 20.9%". Explain to a person who has never had a course in statistics or research methods what it means to use a random-digit-dial method and why it is important.