Final answer:
We select a sample to gain insights into a larger population, using random and representative sampling techniques to ensure accuracy and avoid bias.
Step-by-step explanation:
We select a sample in order to get information about some population. Sampling is a practical method used when it's prohibitively time-consuming or expensive to study an entire population. Examples of sampling include computing the average GPA from a subset of students, conducting opinion polls during elections, and quality control in manufacturing.
In random sampling, every person in a population has an equal chance of being included, which aims to reflect the demographics and opinions of the entire population accurately. This is vital for producing results that are representative of the population without bias. Comprehensive studies by polling companies involve methodologically sound sampling to derive conclusions that policymakers and others may rely upon.
However, it's important to be critical of sampling methods as large samples can be biased. For example, online surveys often suffer from self-selection bias, whereas some population members are not equally likely to be chosen due to the methodology, leading to skewed results. Therefore, samples should be random and representative to avoid such biases and provide accurate data about the population.