This small portion is called a sample. For example, audience ratings of television shows are done this way. To figure out the size of the audience that is watching a particular show, a small group of people are surveyed. Statisticians ask these people which television programs they watched on a particular day. From their responses, statisticians can figure out what percentage of the entire audience watched each show.
Statisticians use their skills to decide where and how to gather the data.
They determine the type and size of the sample group. They also develop the survey questionnaire or reporting form. In addition, statisticians prepare instructions for the workers who will collect the data. Next, statisticians analyze the information. This is done on a computer using special programs.