A statistic is a numerical characteristic of a sample, but a parameter is a numerical characteristic of population.
• Sampling error refers to the difference between the value of a sample statistic, such as the sample mean, and the true value of the population parameter, such as the population mean. Note: some error is always present in sampling. With random sampling methods, the error is random.
• The response rate is the percentage of people in the sample selected for the study who actually participate in the study.
• A sampling frame is just a list of all the people that are in the population