Understanding the Terms

• Population: In the context of a poll, the population is the entire group of people about whom information is wanted. This is typically the adult population of a country.
• Sample: A sample is a subset of the population selected to represent the whole. Pollsters interview a sample of people and use their responses to draw conclusions about the entire population.

An Example: A Presidential Election Poll

Let’s consider a hypothetical presidential election poll conducted by a reputable polling agency.

Population: The population for this poll would be all adult citizens of the United States. This includes people of all ages, races, ethnicities, genders, socioeconomic statuses, and geographic locations within the country.

Sample: The polling agency would select a few thousand adults to participate in the survey. To ensure the sample is representative of the population, they would typically use a random sampling method. This involves selecting individuals randomly from the population to be included in the sample. The sample should mirror the population in terms of demographics like age, gender, race, education, and geographic location.

Key Points

• Sample size: While a few thousand people might seem like a small number compared to the entire adult population, statistical methods allow pollsters to estimate the margin of error and confidence level for their results.
• Sampling methods: The accuracy of a poll heavily relies on the sampling method used. Random sampling is considered the gold standard, but other methods like stratified sampling or cluster sampling can also be effective.
• Margin of error: This indicates the potential range by which the results of the poll may differ from the true opinions of the entire population.
• Confidence level: This expresses the degree of certainty that the true population value falls within the margin of error.

By carefully selecting a sample and using appropriate statistical analysis, pollsters can make reasonably accurate inferences about the opinions of the entire population. However, it’s essential to consider the margin of error and confidence level when interpreting poll results.

Note: To provide a more specific example, you can search for recent polls conducted by reputable organizations like Gallup, Pew Research Center, or FiveThirtyEight. These organizations often publish detailed methodologies explaining their sampling techniques.